Offensive Counter-Air (OCA) is a military term for the suppression of an enemy's military air power by destroying or disabling the aircraft on the ground and/or destroying or crippling the runways and other infrastructure necessary to operate them.

Offensive counter-air strikes have been used since World War I, but perhaps the most successful single OCA mission to date was the Israeli offensive that opened the Six Day War of 1967, when the Heyl Ha'avir destroyed a large portion of the air power of Egypt, Syria, and Jordan, mostly on the ground.

During the 1950s, Cold War strategy of both NATO and the Warsaw Pact called for OCA to be carried out with tactical nuclear weapons, but by the mid-1960s, new policies of 'proportional response' brought about a return to conventional tactics. Beginning shortly before the Six Day War, specialized weapons were developed for disrupting runways, such as the BLU-107 Durandal anti-runway bomb. Various such weapons continue to be fielded, notably the Hunting JP233 munition used by RAF Panavia Tornado aircraft during the 1991 Gulf War.

Although OCA missions are often carried out via air strikes, they are not limited to aerial action. As a common rubric of the Cold War held, a tank parked at the end of an enemy runway is a perfectly valid counter-air weapon.