David Eaglesham, 63, who held the post for 12 years from 1996 to 2008, was described as an"outstanding" general secretary who had made a "huge contribution" to the organisation.
Alan McKenzie, the SSTA's acting general secretary, said: "David brought to the post a sense of tirelessness and, sometimes in the face of much opposition, a determination to change the SSTA and increase its profile nationally.
"Those of us who worked with him remember his huge contribution. We are all deeply saddened by his death following a long illness".
Tributes to Mr Eaglesham, a former principal teacher of modern studies at Cathkin High, Cambuslang, were led by Cabinet Secretary for Education Michael Russell.
He said: "I was saddened to learn of the passing of David Eaglesham, with whom I worked closely when I was in opposition, and whose advice I valued greatly, as did his union members.
"I would offer my condolences to his family and friends. He will be greatly missed. David was committed to serving his fellow teachers through his work with the SSTA and his interests more broadly in Scottish education."
And Larry Flanagan, general secretary of the Educational Institute of Scotland (EIS) teaching union, added: "Everyone associated with the EIS was saddened to hear of the death of former SSTA general secretary David Eaglesham and everyone at the EIS offers condolences to his family, friends and colleagues.
"David was committed to the work of his association, as well as to the cause of Scottish education more generally.
"The EIS has always enjoyed a positive working relationship, both with David personally as well as with the SSTA on issues of mutual interest, through his term as general secretary and beyond."