Oskar Cher (2 September 1913 – 2 June 1942) was an Estonian communist activist.

He worked as a journalist in the early 1930s, and joined the banned Communist Party of Estonia (EKP) in 1933.

After Estonia was occupied by the Soviet Union in 1940, Cher organized the EKP in Läänemaa.

In 1941, he was made secretary of the Leninist Young Communist League of Estonia.

When Nazi Germany occupied Estonia in 1941, Cher joined the communist resistance movement.