AP1

AP1 or AP-1 may refer to:

Biology

 * Activator protein 1, dimeric transcription factor
 * Adaptor protein 1, tetrameric clathrin-associated complex

Transportation

 * Autopista AP-1, a Spanish motorway
 * Caproni A.P.1, a 1934 Italian attack aircraft monoplane
 * USS Henderson (AP-1)

Other uses

 * Protocol I, or AP 1, a 1977 amendment to the Geneva Conventions