Banach is a Polish-language surname of several possible origins. Notable people with this surname include:
Stefan Banach (1892–1945), Polish mathematician
Ed Banach (born 1960), American wrestler
Lou Banach (born 1960), American wrestler
Korneliusz Banach (born 25 January 1994), Polish volleyball player
Łukasz Banach, birth name of Norman Leto (born 1980), Polish artist in the fields of painting, film, and new media
Maurice Banach, German footballer
Michael Banach (born 1962), American archbishop of the Roman Catholic Church
Orest Banach, German-American soccer goalkeeper of Ukrainian descent
William Banach (1903–1951), American politician, member of the Wisconsin State Assembly