Janáček (feminine: Janáčková) is a Czech surname, derived from the given name Jan, the Czech form of John. Notable people with the surname include:
- Jaromír Janáček (born 1995), Czech badminton player
- Jitka Janáčková (born 1973), Czech canoer
- Leoš Janáček (1854–1928), Czech composer
- Liana Janáčková (born 1953), Czech politician
- Libor Janáček (born 1969), Czech footballer
- Štěpán Janáček (born 1977), Czech pole vaulter
- Světlana Janáčková (born 1967), Czech volleyball player
also
edit- Grażyna Prokopek-Janáček (born 1977), Polish sprinter