Press Release

GTT Announces Earnings Call for Fourth Quarter 2015

McLean, VA, February 17, 2016

GTT Communications, Inc. (“GTT”) (NYSE: GTT), the leading global cloud networking provider to multinational clients, announced today its plans to release results for the fourth quarter ended December 31, 2015, on Thursday, March 3, 2016. In conjunction with the release, GTT has scheduled a conference call, which will also be broadcast live over the Internet, that day at 10 a.m. ET. What: GTT’s Fourth Quarter 2015 Financial Results Conference Call When: Thursday, March 3, 2016, at 10 a.m. ET Where: Via phone by dialing +1.866.777.2509 or +1.412.317.5413, entering the passcode 10081281, and asking for the GTT Communications, Inc., call, or via webcast at www.www.gtt.net A telephonic replay of the conference call will be available for one month and may be accessed by calling +1.877.344.7529 or +1.412.317.0088 and using the passcode 10081281. The webcast will be archived in the investor relations section of the company’s website. About GTT GTT’s global Tier 1 IP network enables clients to connect to any location in the world and with any application in the cloud. Our cloud networking services provide a better way for multinational clients to reach the cloud. Clients trust us to deliver secure solutions with simplicity, speed and agility. For more information, visit www.gt t .net . Please contact:

GTT Investor Relations: Jody Burfening/Carolyn Capaccio, LHA +1 212 838 3777 [email protected]

GTT Media Inquiries Ann Rote +1 703 677 9941 [email protected]