Issachar Ber Ryback, also Riback (Іссахар-Бер Рибак; 2 February 1897, in Yelisavetgrad, Russian Empire (today Kropyvnytskyi, Ukraine) – 22 December 1935, in Paris) was a Jewish-Ukrainian-French painter.

In 1916 El Lissitzky and Ryback were given the task to make Jewish art memorials of schtetls from Ukraine and Belarus.

During the October Revolution in 1917, he took part in multiple activities to redefine avantgarde Yiddish culture, e.g., he was a member of Kultur Lige in Kiev.

After his father was killed by Petliura's soldiers in the pogroms in Ukraine, he fled in April 1921 to Kaunas and in October 1921 he obtained a visa for Germany.

Rybak was a contemporary of Jewish-Russian artists Natan Issajewitsch Altman, Boris Aronson and Marc Chagall, who transmitted the Jewish tradition in modern art.