Masao Adachi (足立正生 Adachi Masao, born May 13, 1939) is a Japanese screenwriter and director who was most active in the 1960s and 1970s. He was born in Fukuoka Prefecture.
| Movie | Sekigun-P.F.L.P: Sekai sensô sengen | 1971 |
| Movie | Datai | 1966 |
| Movie | Hinin kakumei | 1967 |
| Movie | Jogakusei gerira | 1969 |
| Movie | 断食芸人 | 2016 |
| Movie | Ryakushô: renzoku shasatsuma | 2013 |
| Movie | Gingakei | 1967 |
| Movie | Wan | 1961 |
| Movie | Sei chitai: Sex zone | 1968 |
| Movie | Hikisakareta jôji | 1966 |
| Movie | Datai | 1966 |
| Movie | Hinin kakumei | 1967 |
| Movie | Jogakusei gerira | 1969 |
| Movie | 断食芸人 | 2016 |
| Movie | Endoresu warutsu | 1995 |
| Movie | 17-sai no fûkei - Shônen wa nani o mita no ka | 2004 |
| Movie | Ryakushô: renzoku shasatsuma | 2013 |
| Movie | Bôgyaku onna gômon | 1978 |
| Movie | Seihanzai | 1968 |
| Movie | Ami no naka no bôkô | 1967 |
| Movie | Segura magura: shinitai onna | 1971 |
| Movie | Mahiru no bôkô-geki | 1970 |
| Movie | Gingakei | 1967 |
| Movie | Kôkôsei burai hikae | 1972 |
| Movie | Uragiri no kisetsu | 1966 |
| Movie | Seizoku: Sex Jack | 1970 |
| Movie | Hika | 1971 |
| Movie | Sei chitai: Sex zone | 1968 |
| Movie | The Ugly One | 2013 |
| Movie | Sei no hôrô | 1967 |
| Movie | Nihon bôkô ankokushi: Onjû | 1970 |
| Movie | Abe ichizoku | 1938 |
| Movie | Shinjuku maddo | 1970 |
| Movie | Seishôjo gômon | 1980 |
| Movie | Ryakushô: renzoku shasatsuma | 2013 |
| Movie | Gingakei | 1967 |
| Movie | Chi wa taiyô yori akai | 1966 |
