UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13A-16 OR 15D-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): October 9, 2014

Commission File Number: 001-34104

NAVIOS MARITIME ACQUISITION CORPORATION

7 Avenue de Grande Bretagne, Office 11B2

Monte Carlo, MC 98000 Monaco

(Address of Principal Executive Offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

x  Form 20-F             ¨  Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ¨

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934:  ¨  Yes    No  x

Information Contained in this Report on Form 6-K

Attached hereto is a copy of the Notice of 2014 Annual Meeting of Stockholders and Proxy Statement of Navios Maritime Acquisition Corporation dated October 9, 2014 for the 2014 Annual Meeting of Stockholders to be held on November 21, 2014.

October 9, 2014

Dear Stockholder,

We cordially invite you to attend our 2014 annual meeting of stockholders to be held at 10:00 a.m., local time, on Friday, November 21, 2014, at our offices at Le Montaigne Bloc B, 7 Avenue de Grande Bretagne, Monaco. The attached notice of annual meeting and proxy statement describe the business we will conduct at the meeting and provide information about Navios Maritime Acquisition Corporation that you should consider when you vote.

When you have finished reading the proxy statement, please promptly vote your interests by marking, signing, dating and returning the proxy card in the enclosed envelope. We encourage you to vote by proxy so that your interests will be represented and voted at the meeting, whether or not you can attend.

Sincerely,

Angeliki Frangou

Chairman and Chief Executive Officer

NAVIOS MARITIME ACQUISITION CORPORATION

NOTICE OF 2014 ANNUAL MEETING OF STOCKHOLDERS

October 9, 2014

TIME: 10:00 a.m., local time

DATE: November 21, 2014

PLACE: Offices of Navios Maritime Acquisition Corporation, Le Montaigne Bloc B, 7 Avenue de Grande Bretagne, Monaco

PURPOSES:

WHO MAY VOTE:

You may vote if you were the record owner of Navios Maritime Acquisition Corporation stock at the close of business on October 8, 2014. A list of stockholders of record will be available at the meeting and, during the 10 days prior to the meeting, at the office of the Secretary at the above address.

BY ORDER OF THE BOARD OF DIRECTORS

Vasiliki Papaefthymiou

Secretary

NAVIOS MARITIME ACQUISITION CORPORATION

LE MONTAIGNE BLOC B

7 AVENUE DE GRANDE BRETAGNE

MONACO

PROXY STATEMENT FOR

NAVIOS MARITIME ACQUISITION CORPORATION

2014 ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD ON NOVEMBER 21, 2014

GENERAL INFORMATION ABOUT THE ANNUAL MEETING

Why Did You Send Me this Proxy Statement?

We sent you this proxy statement and the enclosed proxy card because Navios Maritime Acquisition Corporation’s Board of Directors is soliciting your proxy to vote at the 2014 annual meeting of stockholders and any adjournments of the meeting to be held at 10:00 a.m., local time, on Friday, November 21, 2014, at our offices at Le Montaigne Bloc B, 7 Avenue de Grande Bretagne, Monaco. This proxy statement along with the accompanying Notice of Annual Meeting of Stockholders summarizes the purposes of the meeting and the information you need to know to vote at the annual meeting.

On October 9, 2014, we began sending this proxy statement, the attached notice of annual meeting and the enclosed proxy card to all stockholders entitled to vote at the meeting. You can find a copy of our 2013 Annual Report on Form 20-F on the Internet through our website at www.navios-acquisition.com or the Securities and Exchange Commission’s electronic data system called EDGAR at www.sec.gov.

Who Can Vote?

Only stockholders who owned Navios Maritime Acquisition Corporation common stock at the close of business on October 8, 2014 are entitled to vote at the annual meeting. On this record date, there were 151,664,942 shares of Navios Maritime Acquisition Corporation common stock outstanding and entitled to vote. Navios Maritime Acquisition Corporation common stock is our only class of voting stock. The shares of common stock are listed on the New York Stock Exchange under the symbol “NNA.”

You do not need to attend the annual meeting to vote your shares. Shares represented by valid proxies, received in time for the meeting and not revoked prior to the meeting, will be voted at the meeting. A stockholder may revoke a proxy before the proxy is voted by delivering to our Secretary a signed statement of revocation or a duly executed proxy card bearing a later date. Any stockholder who has executed a proxy card but attends the meeting in person may revoke the proxy and vote at the meeting.

How Many Votes Do I Have?

Each share of Navios Maritime Acquisition Corporation common stock that you own entitles you to one vote.

How Do I Vote?

Whether you plan to attend the annual meeting or not, we urge you to vote by proxy. Voting by proxy will not affect your right to attend the annual meeting. If your shares are registered directly in your name through our stock transfer agent, Continental Stock Transfer & Trust Company, or you have stock certificates, you may vote:

If your shares are held in “street name” (held in the name of a bank, broker or other nominee), you must provide the bank, broker or other nominee with instructions on how to vote your shares and can do so as follows:

How Does the Board of Directors Recommend That I Vote on the Proposals?

The Board of Directors recommends that you vote as follows:

If any other matter is presented, the proxy card provides that your shares will be voted by the proxy holder listed on the proxy card in accordance with his or her best judgment. At the time this proxy statement was printed, we knew of no matters that needed to be acted on at the annual meeting, other than those discussed in this proxy statement.

May I Revoke My Proxy?

If you give us your proxy, you may revoke it at any time before the meeting. You may revoke your proxy in any one of the following ways:

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What Vote is Required to Approve Each Proposal and How are Votes Counted?

What Constitutes a Quorum for the Meeting?

The presence, in person or by proxy, of the holders of no less than a majority of the outstanding shares of our common stock is necessary to constitute a quorum at the meeting. Votes of stockholders of record who are present at the meeting in person or by proxy, abstentions, and broker non-votes are counted for purposes of determining whether a quorum exists.

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ELECTION OF DIRECTORS

(Notice Item 1)

Our Board of Directors consists of seven directors, who are divided into three classes. As provided in our Articles of Incorporation, each director is elected to serve for a three-year term and until such director’s successor is duly elected and qualified, except in the event of such director’s death, resignation, removal or earlier termination of such director’s term of office. The terms of two Class C directors expire at the annual meeting. Accordingly, the Board of Directors has nominated Angeliki Frangou and Anna Kalathakis, each of whom is a Class C director, for election as directors whose terms would expire at our 2017 Annual Meeting of Stockholders.

Unless the proxy is marked to indicate that such authorization is expressly withheld, the persons named in the enclosed proxy intend to vote the shares authorized thereby FOR the election of the following two nominees. It is expected that each of these nominees will be able to serve, but if before the election it develops that any of the nominees is unavailable, the persons named in the accompanying proxy will vote for the election of such substitute nominee or nominees as the current board of directors may recommend.

Nominees for Election as Class C Directors to the Board of Directors

Information concerning the nominees for the Class C directors is set forth below:

Angeliki Frangou has been our Chairman and Chief Executive Officer since our inception in March 2008. Ms. Frangou has also been Chairman and CEO of Navios Maritime Holdings Inc. (NYSE: NM) (“Navios Holdings”) — our sponsor — since August 2005. In addition, Ms. Frangou has been the Chairman and Chief Executive Officer of Navios Maritime Partners L.P. (NYSE: NMM), an affiliated limited partnership, since August 2007, and the Chairman of the Board of Directors of Navios South American Logistics Inc., an affiliated corporation, since its inception in December 2007. Previously, Ms. Frangou served as Chairman, Chief Executive Officer and President of International Shipping Enterprises Inc., which acquired Navios Holdings. From 1990 until August 2005, Ms. Frangou was the Chief Executive Officer of Maritime Enterprises Management S.A. and its predecessor company, which specialized in the management of dry cargo vessels. Ms. Frangou is the Chairman of IRF European Finance Investments Ltd., listed on the SFM of the London Stock Exchange. From September 2012 to June 2013, Ms. Frangou served as a Board member of Eurobank Ergasias S.A. Ms. Frangou is member of the Board of the United Kingdom Mutual Steam Ship Assurance Association (Bermuda) Limited, Vice Chairman of China Classification Society Mediterranean Committee, a member of the International General Committee and of the Hellenic and Black Sea Committee of Bureau Veritas, as well as a member of Greek Committee of Nippon Kaiji Kyokai. Since May 2014, Ms. Frangou has been a Member of the Board of The Hellenic Mutual War Risks Association (Bermuda) Limited. Since July 2013, Ms. Frangou has been a Member of the Board of Visitors of the Columbia University School of Engineering and Applied Science. Ms. Frangou received a bachelor’s degree in mechanical engineering, summa cum laude, from Fairleigh Dickinson University and a master’s degree in mechanical engineering from Columbia University.

Anna Kalathakis has been a member of our Board of Directors and Senior Vice President — Legal Risk Management since May 2010. Ms. Kalathakis has been Chief Legal Risk Officer of Navios Holdings since November 2012, and was Senior Vice President — Legal Risk Management of Navios Holdings from December 2005 until October 2012. Previously, Ms. Kalathakis was the General Manager of the Greek office of A Bilbrough & Co. Ltd. (Managers of the London Steam-Ship Owners’ Mutual Insurance Association Limited, the “London P&I Club”) and an Associate Director of the London P&I Club where she gained experience in the handling of liability and contractual disputes in both the dry and tanker shipping sectors (including collisions, oil pollution incidents, groundings, etc.). She also previously worked for a U.S. maritime law firm in New Orleans,

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having qualified as a lawyer in Louisiana in 1995, and served in a similar capacity for a London maritime law firm. She qualified as a solicitor in England and Wales in 1999 and was admitted to the Piraeus Bar in Greece, in 2003. She received a bachelor’s degree International Relations from Georgetown University and holds a master of business administration degree from European University in Brussels and a juris doctor degree from Tulane Law School.

THE BOARD OF DIRECTORS RECOMMENDS THE ELECTION OF ANGELIKI FRANGOU AND ANNA KALATHAKIS AS CLASS C DIRECTORS, AND PROXIES SOLICITED BY THE BOARD WILL BE VOTED IN FAVOR THEREOF UNLESS A STOCKHOLDER HAS INDICATED OTHERWISE ON THE PROXY.

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INDEPENDENT PUBLIC ACCOUNTANTS

(Notice Item 2)

The Board of Directors is submitting for approval the appointment of PricewaterhouseCoopers, independent public accountants, as our independent auditors for the fiscal year ending December 31, 2014. The Board proposes that the stockholders ratify this appointment. PricewaterhouseCoopers audited our financial statements for the fiscal year ended December 31, 2013.

PricewaterhouseCoopers has advised us that it does not have any direct or indirect financial interest in the company, nor has it had any such interest in connection with us during the past three years other than in its capacity as our independent auditors.

All services rendered by the independent auditors are subject to review by the Audit Committee of our Board of Directors.

In the event the stockholders do not ratify the appointment of PricewaterhouseCoopers as our independent public accountants, the Audit Committee will reconsider its appointment.

The affirmative vote of a majority of the shares present or represented and entitled to vote at the annual meeting is required to ratify the appointment of the independent public accountants.

THE BOARD OF DIRECTORS RECOMMENDS A VOTE TO RATIFY THE APPOINTMENT OF PRICEWATERHOUSECOOPERS AS INDEPENDENT PUBLIC ACCOUNTANTS, AND PROXIES SOLICITED BY THE BOARD WILL BE VOTED IN FAVOR OF SUCH RATIFICATION UNLESS A STOCKHOLDER INDICATES OTHERWISE ON THE PROXY.

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SOLICITATION

The cost of preparing and soliciting proxies will be borne by us. Solicitation on behalf of the Board of Directors will be made primarily by mail, but stockholders may be solicited by telephone, e-mail, other electronic means, or personal contact. Copies of materials for the annual meeting will be supplied to brokers, dealers, banks and voting trustees, or their nominees, for the purpose of soliciting proxies from beneficial owners.

OTHER MATTERS

The Board of Directors knows of no other business which will be presented to the annual meeting. If any other business is properly brought before the annual meeting, proxies in the enclosed form will be voted in accordance with the judgment of the persons voting the proxies.

BY ORDER OF THE BOARD OF DIRECTORS

Vasiliki Papaefthymiou

Secretary

October 9, 2014

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YOUR VOTE IS IMPORTANT. PLEASE VOTE TODAY.

p FOLD HERE — DO NOT SEPARATE — INSERT IN ENVELOPE PROVIDED p

The Board of Directors recommends a vote FOR Proposals 1 and 2.

Note: Please sign exactly as name appears hereon. When shares are held by joint owners, both should sign. When signing as attorney, executor, administrator, trustee, guardian, or corporate officer, please give title as such.

p FOLD HERE — DO NOT SEPARATE — INSERT IN ENVELOPE PROVIDED p

PROXY

THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS

NAVIOS MARITIME ACQUISITION CORPORATION

The undersigned, revoking any previous proxies relating to these shares, hereby acknowledges receipt of the Notice and Proxy Statement dated October 9, 2014 in connection with the Annual Meeting of Stockholders to be held at 10:00 a.m., local time, on Friday, November 21, 2014 at our offices at Le Montaigne Bloc B, 7 Avenue de Grande Bretagne, Monaco and hereby appoints Angeliki Frangou, George Achniotis and Vasiliki Papaefthymiou, and each of them (with full power to act alone), the attorneys and proxies of the undersigned, with power of substitution to each, to vote all shares of the Common Stock of Navios Maritime Acquisition Corporation registered in the name provided in this Proxy which the undersigned is entitled to vote at the 2014 Annual Meeting of Stockholders, and at any adjournments of the meeting, with all the powers the undersigned would have if personally present at the meeting. Without limiting the general authorization given by this Proxy, the proxies are, and each of them is, instructed to vote or act as follows on the proposals set forth in the Proxy.

This Proxy when executed will be voted in the manner directed herein. If no direction is made this Proxy will be voted FOR the election of Directors and FOR Proposal 2.

(Continued and to be marked, dated and signed, on the other side)

Signatures

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.