Olejniczak is a Polish surname, it may refer to: Cezary Olejniczak (born 1972), Polish politician Dawid Olejniczak (born 1983), Polish tennis player Dominic Olejniczak (1908–1989), American mayor Janusz Olejniczak (1952–2024), Polish pianist and actor Michał Olejniczak (born 2001), Polish handball player Stan Olejniczak (1912–1979), American football player Wojciech Olejniczak (born 1974), Polish politician