Click here to view the Fund’s Summary Prospectus STATEMENT OF Click here to view the Fund’s Prospectus ADDITIONAL INFORMATION June 1, 2021 Parametric Emerging Markets Fund Investor Class Shares - EAEMX Class C Shares - ECEMX Institutional Class Shares - EIEMX Class R6 Shares - EREMX Two International Place Boston, Massachusetts 02110 1-800-260-0761 This Statement of Additional Information (“SAI”) provides general information about the Fund. The Fund is a diversified, open-end management investment company. The Fund is a series of Eaton Vance Mutual Funds Trust. Capitalized terms used in this SAI and not otherwise defined have the meanings given to them in the Prospectus. This SAI contains additional information about: Page Page Strategies and Risks 2 Sales Charges 22 Investment Restrictions 4 Disclosure of Portfolio Holdings and Related Information 23 Management and Organization 6 Taxes 24 Investment Advisory and Administrative Services 15 Portfolio Securities Transactions 34 Other Service Providers 18 Potential Conflicts of Interest 37 Calculation of Net Asset Value 19 Financial Statements 43 Purchasing and Redeeming Shares 20 Additional Information About Investment Strategies and Risks 43 Appendix A: Investor Class Fees and Ownership 76 Appendix D: Class R6 Ownership 79 Appendix B: Class C Fees and Ownership 77 Appendix E: Eaton Vance Funds Proxy Voting Policy and Procedures 80 Appendix C: Institutional Class Ownership 78 Appendix F: Parametric Portfolio Associates LLC Proxy Voting Policies and Procedures 82 This SAI is NOT a prospectus and is authorized for distribution to prospective investors only if preceded or accompanied by the Fund Prospectus dated June 1, 2021, as supplemented from time to time, which is incorporated herein by reference. This SAI should be read in conjunction with the Prospectus, which may be obtained by calling 1-800-260-0761. © 2021 Eaton Vance Management Definitions The following terms that may be used in this SAI have the meaning set forth below: “1940 Act” means the Investment Company Act of 1940, as amended; “1933 Act” means the Securities Act of 1933, as amended; “Board” means Board of Trustees or Board of Directors, as applicable; “CEA” means Commodity Exchange Act; “CFTC” means the Commodity Futures Trading Commission; “Code” means the Internal Revenue Code of 1986, as amended; “Eaton Vance family of funds” means all registered investment companies advised or administered by Eaton Vance Management (“Eaton Vance”) or Boston Management and Research (“BMR”); “Eaton Vance funds” means the mutual funds advised by Eaton Vance or BMR; “Exchange” means the New York Stock Exchange; “FINRA” means the Financial Industry Regulatory Authority, Inc.; “Fund” means the Fund or Funds listed on the cover of this SAI unless stated otherwise; “investment adviser” means the investment adviser identified in the prospectus and, with respect to the implementation of the Fund’s investment strategies (including as described under “Taxes”) and portfolio securities transactions, any sub-adviser identified in the prospectus to the extent that the sub-adviser has discretion to perform the particular duties; “IRS” means the Internal Revenue Service; “Portfolio” means a registered investment company (other than the Fund) sponsored by the Eaton Vance organization in which one or more Funds and other investors may invest substantially all or any portion of their assets as described in the prospectus, if applicable; “Subsidiary” means a wholly owned subsidiary that certain funds may have established to pursue their investment objective. No Fund described in this SAI has established a Subsidiary; “SEC” means the U.S. Securities and Exchange Commission; and “Trust” means Eaton Vance Mutual Funds Trust, of which the Fund is a series. STRATEGIES AND RISKS The Fund prospectus identifies the types of investments in which the Fund will principally invest in seeking its investment objective(s) and the principal risks associated therewith. The categories checked in the table below are all of the investments the Fund is permitted to make, including its principal investments and the investment practices the Fund (either directly or through one or more Portfolios as may be described in the prospectus) is permitted to engage in. To the extent that an investment type or practice listed below is not identified in the Fund prospectus as a principal investment strategy, the Fund generally expects to invest less than 5% of its total assets in such investment type. The Fund may hold a security or other instrument that is not otherwise identified as permissible if it is received through a corporate action. If a particular investment type or practice that is checked and listed below but not referred to in the prospectus becomes a more significant part of the Fund’s strategy, the prospectus may be amended to disclose that investment type or practice. Information about the various investment types and practices and the associated risks checked below is included in alphabetical order in this SAI under “Additional Information about Investment Strategies and Risks.” Investment Type Permitted for or Relevant to the Fund Asset-Backed Securities (“ABS”) Auction Rate Securities Build America Bonds Call and Put Features on Securities Collateralized Mortgage Obligations (“CMOs”) Commercial Mortgage-Backed Securities (“CMBS”) Commodity-Related Investments Parametric Emerging Markets Fund 2 SAI dated June 1, 2021 Investment Type Permitted for or Relevant to the Fund Common Stocks ' Contingent Convertible Securities Convertible Securities ' Credit Linked Securities Derivative Instruments and Related Risks ' Derivative-Linked and Commodity-Linked Hybrid Instruments Direct Investments Emerging Market Investments ' Equity Investments ' Equity-Linked Securities ' Event-Linked Instruments Exchange-Traded Funds (“ETFs”) ' Exchange-Traded Notes (“ETNs”) Fixed-Income Securities Foreign Currency Transactions ' Foreign Investments ' Forward Foreign Currency Exchange Contracts ' Forward Rate Agreements ' Futures Contracts Hybrid Securities Illiquid Investments ' Indexed Securities Inflation-Indexed (or Inflation-Linked) Bonds Junior Loans Liquidity or Protective Put Agreements Loans Lower Rated Investments Master Limited Partnerships (“MLPs”) ' Money Market Instruments '(1) Mortgage-Backed Securities (“MBS”) Mortgage Dollar Rolls Municipal Lease Obligations (“MLOs”) Municipal Obligations Option Contracts ' Pooled Investment Vehicles ' Preferred Stock ' Real Estate Investments ' Repurchase Agreements ' Residual Interest Bonds Restricted Securities ' Reverse Repurchase Agreements Rights and Warrants ' Royalty Bonds Senior Loans Parametric Emerging Markets Fund 3 SAI dated June 1, 2021 Investment Type Permitted for or Relevant to the Fund Short Sales Stripped Securities Structured Notes Swap Agreements ' Swaptions Trust Certificates U.S. Government Securities Unlisted Securities ' Variable Rate Instruments When-Issued Securities, Delayed Delivery and Forward Commitments ' Zero Coupon Bonds, Deep Discount Bonds and Payment-In-Kind Securities (“PIK”) Securities Other Disclosures Regarding Investment Practices Asset Coverage ' Average Effective Maturity Borrowing for Investment Purposes Borrowing for Temporary Purposes ' Cybersecurity Risk ' Diversified Status ' Dividend Capture Trading Duration Investing in a Portfolio Investments in the Subsidiary LIBOR Transition and Associated Risk ' Operational Risk ' Option Strategy Participation in the ReFlow Liquidity Program ' Portfolio Turnover ' Restricted Securities ' Securities Lending ' Short-Term Trading Significant Exposure to Health Sciences Companies Significant Exposure to Smaller Companies ' Significant Exposure to Utilities and Financial Services Sectors Tax-Managed Investing (1) Normally not more than 10% of Parametric Emerging Market Fund’s assets will be invested for cash management purposes. INVESTMENT RESTRICTIONS The following investment restrictions of the Fund are designated as fundamental policies and as such cannot be changed without the approval of the holders of a majority of the Fund’s outstanding voting securities, which as used in this SAI means the lesser of: (a) 67% of the shares of the Fund present or represented by proxy at a meeting if the holders of more than 50% of the outstanding shares are present or represented at the meeting; or (b) more than 50% of the outstanding shares of the Fund. Accordingly, the Fund may not: (1) Borrow money or issue senior securities except as permitted by the 1940 Act; Parametric Emerging Markets Fund 4 SAI dated June 1, 2021 (2) Purchase any securities on “margin,” that is to say in a transaction in which it has borrowed all or a portion of the purchase price and pledged the purchased securities or evidences of interest therein as collateral for the amount so borrowed; (3) Engage in the underwriting of securities, except insofar as it may technically be deemed to be an underwriter in selling a portfolio security under circumstances which may require the registration of the same under the Securities Act of 1933; (4) Buy or sell real estate (including interests in real estate limited partnerships) (although it may purchase and sell securities which are secured by real estate and securities of companies which invest or deal in real estate), and commodities or commodity contracts for the purchase or sale of physical commodities; (5) Make loans to other persons, except by (a) the acquisition of debt securities and making portfolio investments, (b) entering into repurchase