Paul Alwin Mittasch (sorbian: Pawol Alwin Mitaš) (born 27 December 1869 in Großdehsa/Dažin, today to Löbau, Germany; died 4 June 1953 in Heidelberg, Germany) was a German chemist and scientific historian of Sorbian descent.
He is well known by his pioneering and systematic research in the development of catalysts for the industrial ammonia synthesis using the Haber–Bosch process.