UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): December 12, 2013

NAVISTAR INTERNATIONAL CORPORATION

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (331)332-5000

(Former name or former address if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

ITEM 5.02 DEPARTURE OF DIRECTORS OR CERTAIN OFFICERS; ELECTION OF DIRECTORS; APPOINTMENT OF CERTAIN OFFICERS; COMPENSATORY ARRANGEMENTS OF CERTAIN OFFICER

Amendments to Navistar Retirement and Savings Plans

On December 12, 2013, the Navistar, Inc. Board of Directors approved amendments to certain employee benefit plans in which certain named executive officers participate. Specifically, amendments were approved to the Navistar, Inc. Managerial Retirement Objective, the Navistar, Inc. Supplement Retirement Accumulation Plan, and to the Navistar, Inc. Supplemental Executive Retirement Plan (collectively, the “Amendments”).

The Amendments include:

The foregoing summary of the Amendments is qualified in its entirety by reference to the copies of the Amendments which are filed herewith.

Approval of Annual Incentive Plan Criteria

In addition to the Amendments, on December 16, 2013, the Compensation Committee of Navistar International Corporation (“Compensation Committee”) approved the Annual Incentive Plan Criteria for fiscal year 2014 for certain employees, including its principal executive officer, principal financial officer and other named executive officers (the “2014 Annual Incentive Awards”).

The Annual Incentive Plan rewards performance based upon the following three financial metrics: 1) market share, weighted at 20% 2) EBITDA, weighted at 40%, and 3) total manufacturing cash, weighted at 40%. The named executive officers are assigned the following Target Award (Percentage of base salary) for fiscal year 2014 Annual Incentive Awards:

Awards are based upon the success of these metrics. Awards are calculated as illustrated in the table below:

The payout multiple of a participant’s Target Award is as follows:

Payout Multiple of Target Award Percentage

ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS.

(d) Exhibits

SIGNATURES

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

Date: December 18, 2013

EXHIBIT INDEX