In StarCraft II, the maximum supply limit for a player is 200. Supply represents the population capacity available for a player's army and worker units.
Players increase supply through race-specific structures and units, including Supply Depots for Terran forces, Pylons for Protoss forces, and Overlords or Overlords upgraded into Overseers for the Zerg. Each race reaches the same overall cap, although the way that capacity is created and protected differs.
The limit is a key strategic constraint rather than a measure of the number of buildings a player may construct. A player who reaches 200 supply must usually destroy or lose units before adding more army units. Some special mission or custom-game rules can alter normal gameplay, but 200 is the standard maximum in competitive StarCraft II.