Lyons will start his new role with immediate effect for the converged technology solutions provider which has offices in Glasgow, Stoke-on-Trent and Northampton.
He brings considerable leadership and security experience to the company, which provides industry-leading solutions and services.
Dr James Dodd, non-executive chairman, will remain on the board as a non-executive director until the company’s annual general meeting in March 2016 while he transitions his responsibilities.
Lyons joins to help the board of directors drive the strategy of the business, and to support the executive management team in both securing acquisitions that will expand Pinnacle Technology Group’s customer base, and in achieving their wider business objectives.
Non-executive director of Pinnacle Technology Group, Tom Black, said: “We believe that Gavin’s experience of buy and builds and track record of achieving transformational growth will be a powerful asset to the company.
“We are certain that his strong track record of success and considerable strategic ability will align with the company’s business objectives, engendering fresh growth.
“As a result, we believe we will be better positioned to expand our solution set across a growing base of customers and be the 'capability partner' of choice."
Lyons has enjoyed a distinguished career in the TMT sector, most recently joining IT security specialist Accumuli PLC as CEO in 2012, and spearheading a successful buy and build strategy that saw it sold to NCC Group plc for £55m in October.
Prior to Accumuli PLC, he was head of telecoms & utilities UK&I at SAP and held various senior positions at Trend Micro, having also worked at Xerox, Compuware and The Caudwell Group.
During his career, he has been involved in three exits, generating close to £100m in value, as well as completing several acquisitions and integrations.