Summary Prospectus    April 1, 2014

MassMutual Select Funds

MassMutual Select Fundamental Growth Fund

Ticker: Class I–MOTZX, Class R5–MOTCX, Service Class–MOTYX, Administrative Class–MOTLX, Class A–MOTAX, Class R4–MFGFX, Class R3–MOTNX

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 and other information about the Fund online at www.massmutual.com/funds. You can also get this information at no cost by calling 1-888-309-3539 or by sending an email request to fundinfo@massmutual.com.

INVESTMENT OBJECTIVE

The 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. 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 $25,000 in MassMutual funds. More information about these and other discounts is available in the section titled Sales Charges by Class on page 127 of the Fund’s Prospectus or from your financial professional.

Shareholder Fees (fees paid directly from your investment)

	Class I	Class R5	Service Class	Adminis- trative Class	Class A	Class R4	Class R3
Maximum Sales Charge (Load) Imposed on Purchases (as a % of offering price)	None	None	None	None	5.75%	None	None
Maximum Deferred Sales Charge (Load) (as a % of the lower of the original offering price or redemption proceeds)	None	None	None	None	None	None	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

	Class I	Class R5	Service Class	Adminis- trative Class	Class A		Class R4	Class R3
Management Fees	.65%	.65%	.65%	.65%		.65%	.65%	.65%
Distribution and Service (Rule 12b-1) Fees	None	None	None	None		.25%	.25%	.50%
Other Expenses(1)	.14%	.24%	.34%	.44%		.44%	.34%	.34%
Total Annual Fund Operating Expenses	.79%	.89%	.99%	1.09%		1.34%	1.24%	1.49%
Expense Reimburse- ment	(.09%)	(.09%)	(.09%)	(.09%)		(.09%)	(.09%)	(.09%)
Total Annual Fund Operating Expenses after Expense Reimburse-ment(2)	.70%	.80%	.90%	1.00%		1.25%	1.15%	1.40%

(1) Other Expenses have been restated to reflect current fees.

(2) The expenses in the above table reflect a written agreement by MML Advisers to cap the fees and expenses of the Fund (other than extraordinary litigation and legal expenses, Acquired Fund fees and expenses, interest expense, short sale dividend and loan expense, or other non-recurring or unusual expenses such as, for example, organizational expenses and shareholder meeting expenses) through March 31, 2015, to the extent that Total Annual Fund Operating Expenses after Expense Reimbursement would otherwise exceed .70%, .80%, .90%, 1.00%, 1.25%, 1.15%, and 1.40% for Classes I, R5, Service, Administrative, A, R4, and R3, respectively. The Total Annual Fund Operating Expenses after Expense Reimbursement shown in the above table may exceed these amounts, because, as noted in the previous sentence, certain fees and expenses are excluded from the cap. The agreement can only be terminated by mutual consent of the Board of Trustees on behalf of the Fund and MML Advisers.

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Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in each share class of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. For Class A shares, the example includes the initial sales charge. The example also assumes that your investment earns a 5% return each year and that the Fund’s operating expenses are exactly as described in the preceding table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	1 Year		3 Years		5 Years		10 Years
Class I	$	72	$	243	$	430	$	970
Class R5	$	82	$	275	$	484	$	1,088
Service Class	$	92	$	306	$	538	$	1,205
Administrative Class	$	102	$	338	$	592	$	1,321
Class A	$	695	$	967	$	1,259	$	2,088
Class R4	$	117	$	385	$	672	$	1,492
Class R3	$	143	$	462	$	805	$	1,772

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. During the most recent fiscal year, the Fund’s portfolio turnover rate was 62% of the average value of its portfolio.

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

The Fund invests primarily in domestic equity securities that the Fund’s subadviser, Wellington Management Company, LLP (“Wellington Management”), believes offer the potential for long-term growth. Equity securities may include common stocks, preferred stocks, securities convertible into common or preferred stock, rights, and warrants, of issuers of any size. While most assets will be invested in equity securities of U.S. companies, the Fund may also invest up to 20% of its total assets in foreign securities and American Depositary Receipts (“ADRs”), including emerging market securities. The Fund may hold a portion of its assets in cash or cash equivalents.

Wellington Management generally employs a bottom-up stock selection process that utilizes

fundamental analysis to identify specific securities within industries or sectors for purchase or sale. Wellington Management seeks to identify diversified sources of return based on its assessment of individual companies against the context of broader market factors by evaluating and ranking each stock on a consistent set of growth, quality, and valuation criteria.

In pursuing its investment objective, Wellington Management has the discretion to purchase some securities that do not meet its normal investment criteria, as described above, when it believes there is an opportunity for substantial appreciation (such as, for example, Wellington Management believes a security could increase in value as a result of a change in management, an extraordinary corporate event, a new product introduction or innovation, or a favorable competitive development). The Fund may sell securities for a variety of reasons, such as to secure gains, limit losses, or redeploy assets into more promising opportunities.

Principal Risks

The following are the Principal Risks of the Fund. You have the potential to make money by investing in the Fund, but you can also lose money.

Cash Position Risk The ability of the Fund to meet its objective may be limited to the extent that it holds assets in cash or otherwise uninvested.

Convertible Securities Risk Convertible securities are subject to the risks of both debt securities and equity securities. The values of convertible securities tend to decline as interest rates rise and, due to the conversion feature, tend to vary with fluctuations in the market value of the underlying common or preferred stock.

Foreign Investment Risk; Emerging Markets Risk; Currency Risk Foreign securities, including ADRs, are subject to additional risks compared to securities of U.S. issuers, including international trade, currency, political, regulatory, and diplomatic risks. In addition, fluctuations in currency exchange rates may adversely affect the values of foreign securities and the price of the Fund’s shares. Emerging markets securities are subject to greater risks than securities issued in developed foreign markets, including less liquidity, greater price volatility, higher relative rates of inflation, greater political, economic, and social instability, greater custody and operational risks, and greater volatility in currency exchange rates. Investments in foreign currencies themselves

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(directly or through derivatives transactions) may be highly volatile and may create investment leverage.

Growth Company Risk The prices of growth securities are often more sensitive to market fluctuations because of their heavy dependence on future earnings expectations, and can be more volatile than the market in general.

Liquidity Risk Certain securities may be difficult (or impossible) to sell or positions difficult to close out at a desirable time and price, and the Fund may be required to hold an investment that is declining in value or be prevented from realizing capital gains.

Management Risk The Fund relies on the manager’s ability to achieve its investment objective. There can be no assurance that the Fund will achieve the desired results and the Fund may incur significant losses.

Market Risk The value of the Fund’s portfolio securities may decline, at times sharply and unpredictably, as a result of unfavorable market-induced changes affecting particular industries, sectors, or issuers. Stock market prices in general may decline over short or extended periods, subjecting the Fund to unpredictable declines in the value of its shares and poor performance. The Fund is subject to risks affecting issuers, such as management performance, financial leverage, industry problems, and reduced demand for goods or services.

Preferred Stock Risk Preferred stocks are subject to the risks associated with other types of equity securities, as well as additional risks, such as potentially greater volatility and risks related to deferral, non-cumulative dividends, subordination, liquidity, limited voting rights, and special redemption rights.

Smaller and Mid-Cap Company Risk Market risk and liquidity risk are particularly pronounced for securities of smaller companies, which may trade less frequently and in smaller volumes than more widely-held securities, and may fluctuate in price more than other securities. Smaller companies may have limited product lines, markets, or financial resources and may be dependent on a limited management group; they may have been recently organized and have little or no track record of success.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

Performance Information

The following bar chart and table provide some indication of the risks of investing in the Fund. The bar chart shows changes in the Fund’s performance from year to year for Class R5 shares. The table shows how the Fund’s average annual returns for 1, 5, and 10 years compare with those of a broad measure of market performance. Performance for Class I and Class R4 shares of the Fund for periods prior to their inception date (04/01/14) is based on the performance of Class R5 shares, adjusted for Class R4 shares to reflect Class R4 expenses. Performance for Class A shares of the Fund reflects any applicable sales charge. The Fund’s name, investment objective, and investment strategy changed on February 22, 2012 to permit the Fund to become “actively” managed. Because the Fund was previously “passively” managed, the performance results shown would likely be different had the Fund’s current investment objective and investment strategy been in effect for the entire period for which performance results are presented. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. More up-to-date performance information is available at http://www.massmutual.com/funds or by calling 1-888-309-3539.

Annual Performance

Class R5 Shares

Highest Quarter: 2Q  ’09, 19.30% Lowest Quarter: 4Q  ’08, - 24.08%

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class R5 only. After-tax returns for other classes will vary.

Average Annual Total Returns

(for the periods ended December 31, 2013)

		One Year		Five Years		Ten Years
Class R5	Return Before Taxes		32.24%		23.38%		8.83%
	Return After Taxes on Distributions		30.79%		23.08%		8.69%
	Return After Taxes on Distributions and Sale of Fund Shares		19.37%		19.29%		7.25%
Class I	Return Before Taxes		32.24%		23.38%		8.83%
Service Class	Return Before Taxes		32.23%		23.19%		8.72%
Administrative Class	Return Before Taxes		32.00%		23.08%		8.57%
Class A	Return Before Taxes		23.96%		21.31%		7.64%
Class R4	Return Before Taxes		31.80%		22.96%		8.45%
Class R3	Return Before Taxes		31.26%		22.33%		7.96%
Russell 1000 Growth Index (reflects no deduction for fees, expenses, or taxes)			33.48%		20.39%		7.84%

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC

Subadviser: Wellington Management Company, LLP

Portfolio Manager: Paul E. Marrkand, CFA is a Senior Vice President and Equity Portfolio Manager at Wellington Management. He has managed the Fund since February 2012.

PURCHASE AND SALE OF FUND SHARES

Shares of the Fund are generally available to retirement plans, other institutional investors, and individual retirement accounts. Fund shares are redeemable on any business day by written request, telephone or internet (available to certain customers).

TAX INFORMATION

The Fund intends to make distributions that may be taxed as ordinary income or capital gains, unless you are an investor eligible for preferential tax treatment.

PAYMENTS TO BROKER-DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase the Fund through a broker-dealer or other financial intermediary, the intermediary may receive a one-time or continuing payments from the Fund, MML Advisers or its affiliates, or others for the sale of Fund shares or continuing shareholder services provided by the intermediary. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary to recommend the Fund over another investment. You should contact your intermediary to obtain more information about the compensation it may receive in connection with your investment.

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