Agatha may refer to:
- Agatha (name), feminine given name
- Agatha (film), a 1979 film about Agatha Christie
- Agatha Award, for mystery and crime writers
- Agatha (genus), a genus of gastropods
- Agatha (Pokémon), a fictional character in the Pokémon franchise
- Agatha, California, a former settlement in Merced County
- Hurricane Agatha (disambiguation), tropical storms and hurricanes called Agatha
- Operation Agatha, British military operation in Palestine, 1946