The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip and provide direction stability. It is analogical to a skeg on boats and ships.

On aircraft, vertical stabilizers generally point upwards. These are also known as the vertical tail, and are part of an aircraft's empennage. The trailing end of the stabilizer is typically movable, and called the rudder; this allows the aircraft pilot to control yaw.

Often navigational radio or airband transceiver antennas are placed on or inside the vertical tail. In most aircraft with three jet engines, the vertical stabilizer houses the central engine or engine inlet duct.

Vertical stabilizers, or fins have also been used in automobiles, specifically in top level motor sports, with the concept making a resurgence in both Formula 1 and Le Mans Prototype racing.

A few aircraft models have a ventral fin under the rear end. Normally this is small, or can fold sideways, to allow landing. The North American X-15 had 4 equal fins round its tail end like a missile's. Also see Dornier Do 335.