The women's 100 metre butterfly competition of the swimming events at the 2012 European Aquatics Championships took place May 24 and 25.

The heats and semifinals took place on May 24, the final on May 25.

[1] Prior to the competition, the existing world, European and championship records were as follows.

39 swimmers participated in 5 heats.

[2] The eight fastest swimmers advanced to the final.