This article explores the activism of Marian Sherman, a churchwoman-turned-atheist in postwar Victoria, British Columbia. Between 1946 and her death in 1975, Sherman promoted atheism and humanism throughout her community, province, and nation. Her secularist journey offers a useful lens on broader changes and continuities in Canada’s postwar religious culture. Broader currents of secularization, including the spread of critical discourse on religion and the rise of secular humanism, contributed to Sherman’s growing prominence as an atheist spokesperson during the 1960s. Responses to Sherman indicate, however, that most atheists continued to feel silenced in this era. Sherman’s outspoken atheism was made possible, in part, by her specific social location, particularly her class, gender, age, and place. This article adds further texture to the picture of religious change in postwar Canada, and demonstrates the significance of women to the making of British Columbian culture in the twentieth century.