An intentional walk, also known as an intentional base on balls (IBB), is a walk issued to a batter by a pitcher with the intent of removing the batters opportunity to swing at the pitched ball. It is a strategic move used by the defensive team to bypass the current batter in order to face the following batter, whom the defensive team expects to be easier to put out. The purpose of an intentional walk is to set up a potential double play or to avoid pitching to a strong hitter.

Intentional walks count as a walk for the hitter and a walk allowed by the pitcher. Prior to the 2017 season, teams had to throw four balls in order to intentionally walk a batter. However, beginning in the 2017 season, teams no longer need to throw four balls in order to intentionally walk a batter. Rather, the manager can signal an intentional walk from the dugout at any point during a plate appearance, putting the batter on first base automatically.

Intentional walks occur most frequently with an excellent hitter at the plate and a significantly worse hitter, or a more favorable matchup for the pitcher, on deck. Generally, intentional walks occur with no one on first base, but they can also occur with first base occupied. The catcher signals the intent to walk the batter by standing up in the catchers box and extending one arm straight to the side away from the batter.

In 2016, there were 932 intentional walks in 2,427 regular season games, one every 2.6 games or an average of 0.38 per game. The new rule allowing managers to signal an intentional walk from the dugout is intended to speed up the game, although observers pointed out that intentional walks were so few, and were usually dispatched so quickly, that the time saved would be minimal.