| Birth Date: | 5 November 1918 |
| Birth Place: | Berlin, German Empire |
| Death Place: | Bonn, West Germany |
| Sport: | Swimming |
| Club: | Nixe Charlottenburg, Berlin; SSF Bonn 1905 |
Gisela Jacob (née Gisela Arendt; 5 November 1918 – 18 February 1969) was a German swimmer who won three medals at the 1934 European Aquatics Championships and two medals at the 1936 Summer Olympics. She also competed at the 1952 Olympics and finished seventh in the 4 × 100 m freestyle relay.
She won eight national titles in the 100 m freestyle (1933–1937, 1939, 1949) and 100 m backstroke (1934), competing as Arendt before World War II and as Jacob after the war.
Her brother, Heinz Arendt, and son, Rainer Jacob, (b. 1946) were both Olympics swimmers, and Heinz competed alongside Gisela at the 1936 Olympics.