Global Sustainable Equity Fund

[JANUS HENDERSON LOGO]

Janus Henderson Global Sustainable Equity Fund

Ticker:	JEASX	Class A Shares	JESSX	Class S Shares	JETNX	Class N Shares
	JECTX	Class C Shares	JEUIX	Class I Shares	JETTX	Class T Shares

Summary Prospectus dated June 25, 2020

Before you invest, you may want to review the Fund’s Prospectus, which contains more information about the Fund and its risks. You can find the Fund’s Prospectus, reports to shareholders, and other information about the Fund online at janushenderson.com/info. You can also get this information at no cost by calling a Janus Henderson representative at 1-877-335-2687 or by sending an email request to prospectusrequest@janushenderson.com.

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from the Fund or your plan sponsor, broker-dealer, or financial intermediary, or if you invest directly with the Fund, by contacting a Janus Henderson representative. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive shareholder reports and other communications from the Fund electronically by contacting your plan sponsor, broker-dealer, or financial intermediary, or if you invest directly with the Fund, by visiting janushenderson.com/edelivery.

You may elect to receive all future reports in paper free of charge. If you do not invest directly with the Fund, you should contact your plan sponsor, broker-dealer, or financial intermediary, to request to continue receiving paper copies of your shareholder reports. If you invest directly with the Fund, you can call 1-800-525-3713 to let the Fund know that you wish to continue receiving paper copies of your shareholder reports. Your election to receive reports in paper will apply to all Janus Henderson mutual funds where held (i.e., all Janus Henderson mutual funds held in your account if you invest through your financial intermediary or all Janus Henderson mutual funds held with the fund complex if you invest directly with a fund).

Investment Objective

Janus Henderson Global Sustainable Equity Fund seeks long-term growth of capital.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold Shares of the Fund. Each share class has different expenses, but represents an investment in the same Fund. For Class A Shares, you may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the Fund or in other Janus Henderson mutual funds. More information about these and other discounts, as well as eligibility requirements for each share class, is available from your financial professional and in the “Purchases” section on page 30 of the Fund’s Prospectus and in the “Purchases” section on page 36 of the Fund’s Statement of Additional Information. In addition, please see Appendix A – Intermediary Sales Charge Waivers and Discounts. You may also incur brokerage commissions charged by your broker or financial intermediary when buying Class I Shares or Class N Shares of the Fund that are not reflected in the table or in the example below.

SHAREHOLDER FEES
(fees paid directly from your investment)

Class A

Class C

Class S

Class I

Class N

Class T

Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price)

5.75%

None

Maximum Deferred Sales Charge (load) (as a percentage of the lower of original purchase price or redemption proceeds)

None

1.00%

None

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ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)	Class A	Class C	Class S	Class I	Class N	Class T
Management Fees	0.75%	0.75%	0.75%	0.75%	0.75%	0.75%
Distribution/Service (12b-1) Fees	0.25%	1.00%	0.25%	None	None	None
Other Expenses⁽¹⁾	0.47%	0.51%	0.66%	0.47%	0.42%	0.66%
Total Annual Fund Operating Expenses⁽²⁾	1.47%	2.26%	1.66%	1.22%	1.17%	1.41%
Fee Waiver⁽²⁾	0.31%	0.31%	0.31%	0.31%	0.31%	0.31%
Total Annual Fund Operating Expenses After Fee Waiver⁽²⁾	1.16%	1.95%	1.35%	0.91%	0.86%	1.10%

(1)

Since the Fund is new, Other Expenses are based on the estimated expenses that the Fund expects to incur in its initial fiscal period.

(2)

Janus Capital has contractually agreed to waive its investment advisory fee and/or reimburse operating expenses to the extent that the Fund’s total annual fund operating expenses (excluding the fees payable pursuant to a Rule 12b-1 plan, shareholder servicing fees, such as transfer agency fees (including out-of-pocket costs), administrative services fees and any networking/omnibus/administrative fees payable by any share class; brokerage commissions; interest; dividends; taxes; acquired fund fees and expenses; and extraordinary expenses) exceed 0.85% until at least June 30, 2021. The contractual waiver may be terminated or modified prior to this date only at the discretion of the Board of Trustees. For a period beginning with the Fund’s commencement of operations (June 25, 2020) and expiring on the third anniversary of the commencement of operations, or when the Fund’s assets meet the first breakpoint in the investment advisory fee schedule (0.75% of the first $2 billion of the average daily closing net asset value of the Fund), whichever occurs first, Janus Capital may recover from the Fund fees and expenses previously waived or reimbursed, which could then be considered a deferral, if the Fund’s expense ratio, including recovered expenses, falls below the expense limit.

EXAMPLE:

The following Example is based on expenses without waivers. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and reinvest all dividends and distributions. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses without waivers or recoupments (if applicable) remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

If Shares are redeemed:	1 Year	3 Years
Class A Shares	$ 716	$ 1,013
Class C Shares	$ 329	$ 706
Class S Shares	$ 169	$ 523
Class I Shares	$ 124	$ 387
Class N Shares	$ 119	$ 372
Class T Shares	$ 144	$ 446

If Shares are not redeemed:	1 Year	3 Years
Class A Shares	$ 716	$ 1,013
Class C Shares	$ 229	$ 706
Class S Shares	$ 169	$ 523
Class I Shares	$ 124	$ 387
Class N Shares	$ 119	$ 372
Class T Shares	$ 144	$ 446

Portfolio Turnover: The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund’s performance. Because the Fund was not in operation during the most recent fiscal year, no portfolio turnover information is available.

Principal investment strategies

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circumstances to maintain investments in securities of issuers or companies that are economically tied to different countries throughout the world, including the United States. The Fund’s investments may be in non-U.S. currency or U.S. dollar-denominated.

The Fund generally invests in a core group of 50-70 equity securities, which consist primarily of common stocks, but may also include other types of instruments, such as depository receipts and warrants. The Fund may also invest in real estate investment trusts (“REITs”). The Fund will invest primarily in larger, well-established companies but may also invest in mid- and small-sized companies. The Fund’s uninvested assets may be held in cash or similar instruments.

In selecting investments, the portfolio managers employ a “bottom-up” approach that focuses on fundamental research and considers, among other factors, a company’s growth potential, competitive positioning, operational quality, and strategy. The portfolio managers may also consider factors such as a company’s historic and projected return on capital, balance sheets, and financial models. In selecting investments, the portfolio managers will also consider environmental, social, and governance (“ESG”) factors that can create sustainable value, such as a company’s supply chain, reputation, brand value, and use of management incentives. Key ESG factors considered as part of the investment process include corporate governance, human capital and diversity, carbon footprint, and business ethics.

The portfolio managers use a screening process to identify companies that are considered to have a potentially negative impact on the development of a sustainable global economy. The screening process, which may employ third-party inputs, is designed to identify issuers whose products or services are considered to negatively impact the environment or society. These companies include issuers based in countries subject to economic sanctions, issuers that stand to be disrupted by the transition to a low-carbon economy, and issuers that engage in activities related to the production or sale of products such as fossil fuels, alcohol, tobacco, and armaments.

The Fund generally sells a stock when, in the portfolio managers’ opinion, there is a deterioration in a company’s fundamentals or a company’s revenue growth has slowed. The Fund may also sell a stock if the portfolio managers believe that a company has achieved its target price or a superior investment opportunity arises. The Fund may also sell a stock if the company’s business model no longer meets the sustainable investment criteria employed in managing the Fund.

Principal investment risks

The biggest risk is that the Fund’s returns will vary, and you could lose money. The Fund invests primarily in common stocks, which tend to be more volatile than many other investment choices.

Market Risk. The value of the Fund’s portfolio may decrease if the value of an individual company or security, or multiple companies or securities, in the portfolio decreases or if the portfolio managers’ belief about a company’s intrinsic worth is incorrect. Further, regardless of how well individual companies or securities perform, the value of the Fund’s portfolio could also decrease if there are deteriorating economic or market conditions. It is important to understand that the value of your investment may fall, sometimes sharply, in response to changes in the market, and you could lose money. Market risk may affect a single issuer, industry, economic sector, or the market as a whole. Market risk may be magnified if certain social, political, economic, and other conditions and events (such as natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest) adversely interrupt the global economy and financial markets.

Sustainable Investment Risk. The Fund follows a sustainable investment approach by investing in companies that relate to certain sustainable development themes and demonstrate adherence to ESG practices. Accordingly, the Fund may have a significant portion of its assets invested in securities of companies conducting similar business or business within the same economic sector. Additionally, due to its exclusionary criteria, the Fund may not be invested in certain industries or sectors. As a result, the Fund may be overweight or underweight in certain industries or sectors relative to its benchmark index, which may cause the Fund’s performance to be more or less sensitive to developments affecting those sectors. In addition, since ESG investing takes into consideration factors beyond traditional financial analysis, the investment opportunities for the Fund may be limited at times. Further, the regulatory landscape for ESG investing in the United States is still developing and future rules and regulations may require the Fund to modify or alter its investment process. Similarly, government policies incentivizing companies to engage in ESG practices may fall out of favor, which could potentially limit the Fund’s investment universe. There is also a risk that the companies identified through the investment process may fail to adhere to ESG practices, which may cause the Fund to sell a security when it might otherwise be disadvantageous to do so.

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Industry and Sector Risk. Although the Fund does not concentrate its investments in specific industries or industry sectors, it emphasizes certain themes and megatrends. As a result, at times, it may have a significant portion of its assets invested in securities of companies conducting similar business or businesses within the same economic sector or that benefit from the same megatrend. Companies in the same industry or economic sector or that benefit from the same megatrend may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments than funds that invest more broadly. As the Fund’s portfolio becomes more concentrated, the Fund is less able to spread risk and potentially reduce the risk of loss and volatility. In addition, the Fund may be overweight or underweight in certain industries or sectors relative to its benchmark index due to its ESG focus, which may cause the Fund’s performance to be more or less sensitive to developments affecting those sectors.

Currency Risk. The Fund’s investments and strategies will involve exposure to foreign currencies. Currency risk is the risk that changes in the exchange rate between currencies will adversely affect the value (in U.S. dollar terms) of an investment. As long as the Fund holds a foreign security, its value will be affected by the value of the local currency relative to the U.S. dollar. When the Fund sells a foreign currency denominated security, its value may be worth less in U.S. dollars even if the security increases in value in its home country. U.S. dollar-denominated securities of foreign issuers may also be affected by currency risk, as the value of these securities may also be affected by changes in the issuer’s local currency.

Foreign Exposure Risk. The Fund normally has significant exposure to foreign markets as a result of its investments in foreign securities, including investments in emerging markets, which can be more volatile than the U.S. markets. As a result, its returns and net asset value may be affected to a large degree by fluctuations in currency exchange rates or political or economic conditions in a particular country. In some foreign markets, there may not be protection against failure by other parties to complete transactions. It may not be possible for the Fund to repatriate capital, dividends, interest, and other income from a particular country or governmental entity. In addition, a market swing in one or more countries or regions where the Fund has invested a significant amount of its assets may have a greater effect on the Fund’s performance than it would in a more geographically diversified portfolio. The Fund’s investments in emerging market countries may involve risks greater than, or in addition to, the risks of investing in more developed countries.

Small- and Mid-Sized Companies Risk. The Fund’s investments in securities issued by small- and mid-sized companies, which can include smaller, start-up companies offering emerging products or services, may involve greater risks than are customarily associated with larger, more established companies. Securities issued by small- and mid-sized companies tend to be more volatile and somewhat more speculative than securities issued by larger or more established companies and may underperform as compared to the securities of larger or more established companies.

Real Estate Securities Risk. The Fund’s performance may be affected by the risks associated with investments in real estate-related companies. The value of real estate-related companies’ securities is sensitive to changes in real estate values and rental income, property taxes, interest rates, tax and regulatory requirements, supply and demand, and the management skill and creditworthiness of the company. Investments in REITs involve the same risks as other real estate investments. In addition, a REIT could fail to qualify for tax-free pass-through of its income under the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”) or fail to maintain its exemption from registration under the Investment Company Act of 1940, as amended, which could produce adverse economic consequences for the REIT and its investors, including the Fund.

New/Smaller Sized Fund Risk. Because the Fund is relatively new, it has a limited operating history and a small asset base. The Fund’s performance may not represent how the Fund is expected to or may perform in the long term if and when it becomes larger. If a new or smaller fund were to fail to attract sufficient assets to achieve or maintain economies of scale, performance may be negatively impacted, and any resulting liquidation could create negative transaction costs for the Fund and tax consequences for investors.

Management Risk. The Fund is an actively managed investment portfolio and is therefore subject to the risk that the portfolio managers may not be successful in identifying investment opportunities that are aligned with the sustainable investment approach that the Fund employs. The Fund may underperform its benchmark index or other mutual funds with similar investment objectives.

An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

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Performance information

The Fund does not have a full calendar year of operations. Performance information for certain periods will be included in the Fund’s first annual and/or semiannual report and is available at janushenderson.com/performance or by calling 1-800-335-2687.

Management

Investment Adviser: Janus Capital Management LLC

Portfolio Managers: Hamish Chamberlayne, CFA, is Executive Vice President and Co-Portfolio Manager of the Fund, which he has co-managed since inception. Aaron Scully, CFA, is Executive Vice President and Co-Portfolio Manager of the Fund, which he has co-managed since inception.

Purchase and sale of Fund shares

Minimum Investment Requirements*

Class A Shares, Class C Shares**, Class S Shares, and Class T Shares
Non-retirement accounts	$ 2,500***
Certain tax-advantaged accounts or UGMA/UTMA accounts	$ 500
Class I Shares
Institutional investors (investing directly with the Fund)	$ 1,000,000
Through an intermediary institution
• non-retirement accounts	$ 2,500
• certain tax-advantaged accounts or UGMA/UTMA accounts	$ 500
Class N Shares
Retirement investors (investing through an adviser-assisted, employer-sponsored retirement plan)	None
Retail investors (investing through a financial intermediary omnibus account)	$2,500****
Institutional investors (investing directly with the Fund)	$ 1,000,000

*	Exceptions to these minimums may apply for certain tax-advantaged, tax-qualified and retirement plans, including health savings accounts, accounts held through certain wrap programs, and certain retail brokerage accounts.
**	The maximum purchase in Class C Shares is $500,000 for any single purchase.
***	Shareholders who invest through financial intermediaries with supermarket and/or self-directed brokerage platforms that maintain omnibus accounts and charge asset-based service fees may not be subject to this minimum. Please contact your financial intermediary for more information.
****	Investors in certain tax-advantaged accounts or accounts held through certain wrap programs may not be subject to this minimum.

Purchases, exchanges, and redemptions can generally be made only through institutional channels, such as financial intermediaries and retirement platforms. Class I Shares may be purchased directly by certain institutional investors who established Class I Shares accounts before August 4, 2017. You should contact your financial intermediary or refer to your plan documents for information on how to invest in the Fund. Requests must be received in good order by the Fund or its agents (financial intermediary or plan sponsor, if applicable) prior to the close of the regular trading session of the New York Stock Exchange in order to receive that day’s net asset value. For additional information, refer to “Purchases,” “Exchanges,” and/or “Redemptions” in the Prospectus.

Tax information

The Fund’s distributions are taxable, and will be taxed as ordinary income or capital gains, unless you are investing through a tax-advantaged arrangement, such as a 401(k) plan or an individual retirement account (in which case you may be taxed upon withdrawal of your investment from such account).

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Payments to broker-dealers and other financial intermediaries

If you purchase Class A Shares, Class C Shares, Class S Shares, Class I Shares, or Class T Shares of the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment or to recommend one share class over another. There is some regulatory uncertainty concerning whether marketing support or other similar payments may be made or received in connection with Class I Shares where a financial intermediary has imposed its own sales charges or transaction fees. As a result, based on future regulatory developments, such payments may be terminated, or the Fund may prohibit financial intermediaries from imposing such sales charges or transaction fees in connection with Class I Shares. Ask your salesperson or visit your financial intermediary’s website for more information.

6	Janus Investment Fund

[JANUS HENDERSON LOGO]

Janus Henderson Global Sustainable Equity Fund

Ticker:

JEDTX

Class D Shares*

* Effective July 6, 2020, Class D Shares are open to new investors. Until that time, Class D Shares remain closed to new investors, with certain limited exceptions.

Summary Prospectus dated June 25, 2020

Before you invest, you may want to review the Fund’s Prospectus, which contains more information about the Fund and its risks. You can find the Fund’s Prospectus, reports to shareholders, and other information about the Fund online at janushenderson.com/reports. You can also get this information at no cost by calling a Janus Henderson representative at 1-800-525-3713 or by sending an email request to prospectusorder@janushenderson.com.

Investment Objective

Janus Henderson Global Sustainable Equity Fund seeks long-term growth of capital.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold Shares of the Fund.

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)		Class D
Management Fees		0.75%
Other Expenses⁽¹⁾		0.62%
Total Annual Fund Operating Expenses⁽²⁾		1.37%
Fee Waiver⁽²⁾		0.37%
Total Annual Fund Operating Expenses After Fee Waiver⁽²⁾		1.00%

(1)

Since the Fund is new, Other Expenses are based on the estimated expenses that the Fund expects to incur in its initial fiscal period.

(2)

Janus Capital has contractually agreed to waive its investment advisory fee and/or reimburse operating expenses to the extent that the Fund’s total annual fund operating expenses (excluding administrative services fees (including out-of-pocket costs), brokerage commissions, interest, dividends, taxes, acquired fund fees and expenses, and extraordinary expenses) exceed 0.85% until at least June 30, 2021. The contractual waiver may be terminated or modified prior to this date only at the discretion of the Board of Trustees. For a period beginning with the Fund’s commencement of operations (June 25, 2020) and expiring on the third anniversary of the commencement of operations, or when the Fund’s assets meet the first breakpoint in the investment advisory fee schedule (0.75% of the first $2 billion of the average daily closing net asset value of the Fund), whichever occurs first, Janus Capital may recover from the Fund fees and expenses previously waived or reimbursed, which could then be considered a deferral, if the Fund’s expense ratio, including recovered expenses, falls below the expense limit. There is no guarantee that the Fund’s assets will reach this asset level.

EXAMPLE:

The following Example is based on expenses without waivers. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, reinvest all dividends and distributions, and then redeem all of your Shares at the end of each period. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating

1	Janus Henderson Global Sustainable Equity Fund

expenses without waivers or recoupments (if applicable) remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	1 Year	3 Years
Class D Shares	$ 139	$ 434

Principal investment strategies

The Fund pursues its investment objective by investing, under normal circumstances, at least 80% of its net assets (plus any borrowings for investment purposes) in equity securities. The Fund will typically invest in companies whose products and services are considered by the portfolio managers as contributing to positive environmental or social change and sustainable economic development, including those that are strategically aligned with environmental and social megatrends such as climate change, resource constraints, growing populations, and aging populations. The Fund expects under normal circumstances to maintain investments in securities of issuers or companies that are economically tied to different countries throughout the world, including the United States. The Fund’s investments may be in non-U.S. currency or U.S. dollar-denominated.

Principal investment risks

The biggest risk is that the Fund’s returns will vary, and you could lose money. The Fund invests primarily in common stocks, which tend to be more volatile than many other investment choices.

2	Janus Investment Fund

investment may fall, sometimes sharply, in response to changes in the market, and you could lose money. Market risk may affect a single issuer, industry, economic sector, or the market as a whole. Market risk may be magnified if certain social, political, economic, and other conditions and events (such as natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest) adversely interrupt the global economy and financial markets.

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“Internal Revenue Code”) or fail to maintain its exemption from registration under the Investment Company Act of 1940, as amended, which could produce adverse economic consequences for the REIT and its investors, including the Fund.

An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Performance information

Management

Investment Adviser: Janus Capital Management LLC

Purchase and sale of Fund shares

Minimum Investment Requirements
To open a new regular Fund account	$2,500
To open a new regular Fund account with an automatic investment program of $50 per month	$ 100
To open a new UGMA/UTMA account, Coverdell Education Savings Account, or a retirement Fund account
• without an automatic investment program	$1,000
• with an automatic investment program of $50 per month	$ 100
To add to any existing type of Fund account without an automatic investment program	$ 50

You may generally purchase, exchange, or redeem Fund Shares on any business day by written request, wire transfer, telephone, and in most cases, online at janushenderson.com/individual. You may conduct transactions by mail (Janus Henderson, P.O. Box 219109, Kansas City, MO 64121-9109), or by telephone at 1-800-525-3713. Purchase, exchange, or redemption requests must be received in good order by the Fund or its agents prior to the close of the regular trading session of the New York Stock Exchange in order to receive that day’s net asset value. For additional information, refer to “To Open an Account or Buy Shares,” “To Exchange Shares,” and/or “To Sell Shares” in the Prospectus.

Tax information

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Payments to broker-dealers and other financial intermediaries

With respect to share classes not offered in this Prospectus, the Fund and its related companies pay select broker-dealer firms or other financial intermediaries for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing a broker-dealer or other intermediary or a salesperson to recommend the Fund over another investment or to recommend one share class over another.

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