Aleksandar Živojinović, born August 27, 1953) better known by his stage name Alex Lifeson, is a Canadian musician, best known as the guitarist of the Canadian rock band Rush.

In the summer of 1968, Lifeson co-founded the band that would become Rush. Other co-founders are friend and drummer John Rutsey, bassist and lead vocalist Jeff Jones, and Jones's successor, current front man Geddy Lee a month later. Lifeson has been an integral member of the band ever since.