Humphries was born in the suburb of Kew in Melbourne, Victoria, the son of Eric Humphries (John Albert Eric Humphries), a construction manager, and his wife Louisa Agnes (Brown). His grandfather was an emigrant to Australia from Manchester, England. His father was well-to-do and Barry grew up in a "clean, tasteful, and modern home" on Christowel Street, Camberwell, then one of Melbourne's new "garden suburbs". His early home life set the pattern for his eventual stage career; his parents bought him everything he wanted, but his father in particular spent little time with him, and Humphries spent hours playing at dressing-up in the back garden.