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

May 6, 2020

Date of Report (Date of earliest event reported)

RIBBON COMMUNICATIONS INC.

(Exact Name of Registrant as Specified in its Charter)

4 TECHNOLOGY PARK DRIVE, WESTFORD, MASSACHUSETTS 01886

(Address of Principal Executive Offices) (Zip Code)

(978) 614-8100

(Registrant’s telephone number, including area code)

N/A

(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 (see General Instruction A.2. below):

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On May 6, 2020, in response to current industry-wide conditions, including the uncertainty created by the effects of the novel coronavirus (COVID-19), the Compensation Committee of the Board of Directors of Ribbon Communications Inc. (“we,” “us,” or “our”) approved, and our executive leadership team agreed, to reduce the executive leadership team’s base salaries. Our President and Chief Executive Officer, Bruce McClelland, has agreed to reduce his base salary by 50% and members of each executive leadership team, including our executive officers, have agreed to reduce their base salaries by 20%. Each of these salary reductions will be effective as of May 15, 2020 and is expected to be in effect for at least 60 days.

In addition, each non-employee member of our Board of Directors has agreed to reduce their annual cash retainer by 50% for the same period in which Mr. McClelland’s base salary reduction remains in effect.

SIGNATURE

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.