Summary Prospectus    May 1, 2015

MML Series Investment Fund

MML Large Cap Growth Fund

Initial Class, Service Class

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

This Fund seeks long-term capital appreciation.

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. The expenses in the table do not reflect deductions at the separate account level or contract level for any charges that may be incurred under a variable life insurance or variable annuity contract. If these charges were reflected, the fees and expenses in the table would be higher.

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

	Initial Class	Service Class
Management Fees	.65%	.65%
Distribution and Service (Rule 12b-1) Fees	N/A	.25%
Other Expenses	.04%	.04%
Total Annual Fund Operating Expenses	.69%	.94%

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. 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. If separate account or variable life insurance or variable annuity contract expenses were included, overall expenses would be higher. 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
Initial Class	$	70	$	221	$	384	$	859
Service Class	$	96	$	300	$	520	$	1,155

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. 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 77% of the average value of its portfolio.

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

The Fund invests primarily in large-capitalization companies that the Fund’s subadviser, Rainier Investment Management, LLC (“Rainier”), believes offer the potential for long-term growth. Under normal circumstances, the Fund invests at least 80% of its net assets in the common stocks of companies whose market capitalizations at the time of purchase are within the market capitalization range of companies included in the Russell 1000^® Growth Index (as of February 28, 2015, $246 million to $748.46 billion). The Fund has the flexibility to invest in companies of any size, including small-capitalization companies (when Rainier believes such companies to be especially attractive). The Fund typically invests most of its assets in equity securities of U.S. companies, but may invest up to 25% of its total assets in foreign securities and American Depositary Receipts (“ADRs”), including emerging market securities. Equity securities may include common stocks, rights, and warrants. The Fund may hold a portion of its assets in cash or cash

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equivalents. The Fund will normally be invested in 40-80 securities. The Fund seeks to invest over a broad cross-section of economic sectors and industries.

In selecting securities, Rainier generally seeks to identify companies that it believes are likely to demonstrate superior earnings growth relative to their peers. Rainier typically favors companies that it believes have attractive fundamentals, such as strong revenue, earnings, or cash flow growth. Companies with sustainable competitive advantages, potential price or business catalysts, including earnings surprise or market expansion, and disciplined management with shareholder focus are emphasized. Rainier also seeks to capture the capital appreciation sometimes associated with high-performing companies identified early in their growth cycles. For emerging companies lacking demonstrated financial results, the strength of the company’s business model, management team, and competitive position are given greater analytical emphasis. To help control risk, Rainier typically compares the Fund’s economic sector weightings to those of a broad index, and normally avoids extreme overweighting or underweighting relative to the index.

Principal Risks

The following are the Principal Risks of the Fund. The value of your investment in the Fund could go down as well as up. You can lose money by investing in the Fund.

Cash Position Risk If the Fund holds a significant portion of its assets in cash or cash equivalents, its investment returns may be adversely affected and the Fund may not achieve its investment objective.

Foreign Investment Risk; Emerging Markets Risk; Currency Risk Investments in securities of non-U.S. issuers (including depositary receipts) entail risks not typically associated with investing in securities of U.S. issuers. Similar risks may apply to securities traded on a U.S. securities exchange that are issued by companies with significant exposure to non-U.S. countries. In certain countries, legal remedies available to investors may be more limited than those available with regard to U.S. investments. Because non-U.S. securities are normally denominated and traded in currencies other than the U.S. dollar, the value of the Fund’s assets may be affected favorably or unfavorably by currency exchange rates, exchange control regulations, and restrictions or prohibitions on the repatriation of non-U.S. currencies. Income

and gains with respect to investments in certain countries may be subject to withholding and other taxes. There may be less information publicly available about a non-U.S. company than about a U.S. company, and many non-U.S. companies are not subject to accounting, auditing, and financial reporting standards, regulatory framework and practices comparable to those in the U.S. The securities of some non-U.S. companies, especially those in emerging markets, are less liquid and at times more volatile than securities of comparable U.S. companies. 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. Non-U.S. transaction costs, such as brokerage commissions and custody costs may be higher than in the United States. In addition, there may be a possibility of nationalization or expropriation of assets, imposition of currency exchange controls, confiscatory taxation, political or financial instability, and diplomatic developments that could adversely affect the values of the Fund’s investments in certain non-U.S. countries.

Growth Company Risk The prices of growth securities are often highly 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 illiquid investment that is declining in value, or it may be required to sell certain illiquid investments at a price or time that is not advantageous in order to meet redemptions or other cash needs. Some securities may be subject to restrictions on resale.

Management Risk The Fund relies on the manager’s investment analysis and its selection of investments to achieve its investment objective. There can be no assurance that the Fund will achieve the intended 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,

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sectors, or issuers. Stock markets can decline significantly in response to issuer, market, economic, industry, political, regulatory, geopolitical and other conditions, as well as investor perceptions of these conditions. The Fund is subject to risks affecting issuers, such as management performance, financial leverage, industry problems, and reduced demand for goods or services.

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. Their shares can be less liquid than those of larger companies, especially during market declines. 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 Initial Class shares. The table shows how the Fund’s average annual returns for 1 and 5 years, and since inception, compare with those of a broad measure of market performance. Performance for Service Class shares of the Fund for periods prior to its inception date (08/15/08) is based on the performance of Initial Class shares, adjusted to reflect Service Class expenses. Performance shown does not reflect the fees and expenses deducted under the variable life insurance or variable annuity contract through which you invest in the Fund. If these amounts were reflected, returns would be less than those shown. Past performance is not necessarily an indication of how the Fund will perform in the future.

Annual Performance

Initial Class Shares

Highest Quarter: 1Q  ’12, 16.63% Lowest Quarter: 4Q  ’08, - 21.52%

Average Annual Total Returns

(for the periods ended December 31, 2014)

		One Year		Five Years		Since Inception (05/01/06)
Initial Class	MML Large Cap Growth Fund		9.51%		14.16%		6.44%
Service Class	MML Large Cap Growth Fund		9.23%		13.86%		6.19%
Russell 1000 Growth Index (reflects no deduction for fees, expenses, or taxes)			13.05%		15.81%		8.84%

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC

Subadviser: Rainier Investment Management, LLC

Portfolio Managers:

Mark H. Dawson, CFA is the Chief Investment Officer and a Principal at Rainier. He has managed the Fund since May 2009.

Michael Emery, CFA is a Senior Equity Portfolio Manager and Principal at Rainier. He has managed the Fund since May 2009.

PURCHASE AND SALE OF FUND SHARES

Shares of the Fund are generally available to separate investment accounts of variable life insurance and variable annuity contracts offered by companies such as MassMutual. An investor should consult the company issuing the investor’s variable life insurance or variable annuity contract to determine how to make redemptions.

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TAX INFORMATION

Dividends and capital gain distributions are paid to the insurance company separate accounts. Variable life insurance and variable annuity contract owners should refer to the variable life insurance or variable annuity product prospectus or consult with their own tax adviser for information regarding the tax consequences of their investment.

PAYMENTS TO INSURANCE COMPANIES AND THEIR AFFILIATES

The Fund is not sold directly to the general public but instead is offered as an underlying investment option

for variable insurance contracts. The Fund and its related companies may make payments to the sponsoring insurance company (or its affiliates) for distribution and/or other services. These payments may be a factor that the insurance company considers in including the Fund as an underlying investment option in the variable insurance contract or may create a conflict of interest by influencing the insurance company or other intermediary to recommend the variable insurance contract over another investment. The prospectus (or other offering document) for your variable insurance contract may contain additional information about these payments.

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