Konstantin Mikhailovich Sergeyev (Russian: Константин Михайлович Сергеев); b. March 5, 1910 (February 20, Old Style) - April 1, 1992) was a Russian danseur, artistic director and choreographer for the Kirov Theatre.
His teachers at Leningrad State Choreographic Institute: Mariya Kojukhova, Vladimir Ponomaryov, Viktor Semyonov (Marina Semyonova’s first husband).
He was married to prima ballerina Feya Balabina (first wife) and Natalia Dudinskaya (second wife), the theatre's prima ballerina too.
Galina Ulanova was his partner between 1930 and 1940. Sergeyev and Ulanova were the first to dance Romeo and Juliet in Sergey Prokofiev's ballet of the same name. Sergeyev was named a People's Artist of the USSR in 1957 and a Hero of Socialist Labor in 1991. He was the recipient of four Stalin Prizes.