The Oracle of the City of San Francisco, also known as the San Francisco Oracle, was an underground newspaper published in 12 issues from September 20, 1966, to February 1968 in the Haight-Ashbury neighborhood of that city. Allen Cohen (1940–2004), the editor during the paper's most vibrant period, and Michael Bowen, the art director, were among the founders of the publication. The Oracle was an early member of the Underground Press Syndicate.

The terms underground press or clandestine press refer to periodicals and publications that are produced without official approval, illegally or against the wishes of a dominant group. In specific recent Asian, American and Western European context, the term "underground press" has most frequently been employed to refer to the independently published and distributed underground papers associated with the counterculture of the late 1960s and early 1970s in India and Bangladesh in Asia, in the United States and Canada in North America, and the United Kingdom and other western nations. It can also refer to the newspapers produced independently in repressive regimes. In German occupied Europe, for example, a thriving underground press operated, usually in association with the Resistance. Other notable examples include the samizdat and bibuła, which operated in the Soviet Union and Poland respectively, during the Cold War.