Rustam Dushmanziyar (Persian: رستم دشمنزار) was a Daylamite aristocrat and the ancestor of the Kakuyid dynasty. His personal name was Rustam, but was known as Dushmanziyar, which is the Daylami version of the Persian word Dushmanzar ("he who brings grief to his enemy").
Rustam, because of his great service to Fakhr al-Dawla, was rewarded with land in Alborz in appreciation of his services. His duty was to protect Ray and northern Jibal against the local leaders from Tabaristan.[4] He later died at an unknown date before 1007, which was the date Muhammad ibn Rustam Dushmanziyar established the Kakuyid dynasty.