Masoud Kimiai or Masud Kimiaei (Persian: مسعود کیمیایی‎‎, born 29 July 1941 in Tehran) is an Iranian director, screenwriter and producer. Kimiai started his career as an assistant director and made his debut, Come Stranger, in 1968. With his second film, Qeysar (1969), he and Dariush Mehrjui with The film The Cow, caused a historical change in Iranian film industry. But Dariush Mehrjui's film with more artistic values has sustained its level of greatness through history of Iranian cinema. Qeysar became a great success at the box office and opened the way for young, talented filmmakers who never had a chance in the industry before.

His films deal with people at the margin of the society with his anti-hero characters that die at the end. Many directors of commercial films imitated his Kaiser/ Qeysar for about 6 years, but in the last decade he focuses on young antagonists. He usually writes his screenplays, using slang dialogs based on ordinary traditional people’s dialect but some Iranians find those dialogues unrealistic and weird.

In 1991, he was awarded a prize in 41st Berlin International Film Festival for his Snake Fang. This was not his sole international prize. At the Cairo International Film festival in 1979 he got from the International Catholic Organisation for Cinema (OCIC), the OCIC Prize for his film The Journey of the Stone. The international OCIC jury gave its award to this film because The Journey of the Stone denounced the exploitation of mankind by mankind and called for a more just social order. Crime directed by Kimiai Winner Crystal Simorgh Best Film in Fajr International Film Festival 2011.

He has been married 3 times. He was married to the late Iranian pop singer Giti Pashaei until 1991, afterwards he married the Iranian pop singer Googoosh.