Keiji Sada was a Japanese actor. He won the award for Best Actor at the 7th Blue Ribbon Awards for Anata Kaimasu (I Will Buy You) and Taifū Sōdōki (Typhoon). He was the father of the actor Kiichi Nakai. Sada is primarily known for starring in Ozu films, especially in the 1950s and most famously Good Morning (1959). He also was a supporting actor in two films of Masaki Kobayashi's Human Condition trilogy. Sada was born in Kyoto in 1926. While a student, he roomed at a boarding house owned by the actor Shuji Sano, and on graduation was offered a position at Shochiku Studios. He was paired with Kinuyo Tanaka for his debut appearance, Keisuke Kinoshita's Phoenix.

Sada was killed in a car crash in 1964. His wife and children were unharmed. He was 37.