Trespass is the second studio album by the English rock band Genesis. It was released in October 1970 on Charisma Records, and is their last album with original guitarist Anthony Phillips and their only one with drummer John Mayhew.

Genesis turned professional in autumn 1969, and began to rehearse intensely and play live shows. After several months of touring they secured a recording contract with Charisma Records, and entered Trident Studios in London in June 1970 to record Trespass. The music marked a departure from more pop-oriented songs, as displayed on their first album From Genesis to Revelation, towards folk-flavoured progressive rock. This ranged from light acoustic pieces with multiple twelve-string guitars such as "Dusk", to the heavier live favorite "The Knife". The sleeve, featuring a knife slash across the front, was the first of several to be designed by Paul Whitehead.

Shortly after recording, Phillips decided to leave the group, which almost caused Genesis to split. After discussing the situation, they agreed to continue, and replaced Mayhew with drummer and singer Phil Collins. Trespass was not a major success upon release; it failed to chart in the UK and the US and it received some mixed reviews from critics, but it was commercially successful in Belgium, which helped sustain the band's career. A reissue briefly charted the UK top 100 in 1984.