George Parker Bidder was a British marine biologist who primarily studied sponger. He was President of the Marine Biological Association from 1939-1945.
He studied zoology at University College London under Ray Lankester for one year before joining Trinity College, Cambridge, where he took the Natural Sciences Tripos until 1886. In 1887 he began working at the Stazione Zoological in Naples, Italy. He joined the MBA in 1893, becoming a member of the council in 1899