WSA may refer to:
- van der Waals surface area
- War Shipping Administration, part of the US government responsible for building cargo ships in World War II.
- Weapon storage area, a maximum security part of an ammunition depot where nuclear weapons are stored.
- Western Sahara Authority
- Western Soccer Alliance
- Windows Socket API, Microsoft's implementation of Berkeley sockets
- Worker Student Alliance, a division of Students for a Democratic Society, sometimes referred to as SDS-WSA
- Workers Solidarity Alliance
- World Service Authority
- World Shovepenny Association
- World Sports Alliance
- World Steel Association
- World Stupidity Awards
- World Summit Award
- WSA Process, Wet gas Sulphuric Acid is a Wet Catalysis Process