Kōji Mitsui (三井弘次, Mitsui Kōji, 6 March 1910 – 20 April 1979) was a Japanese actor. He appeared in more than 150 films from 1925 to 1975, including 29 of Kinema Junpo’s annual Top-10 winners and three of its 10 best Japanese films of all time. In 2000 the magazine named him one of the 60 most important Japanese actors of the 20th century.