Philip Ridder (1759 - 1838) was a Russian explorer who discovered polymetallicores in north-eastern Kazakhstan.
A town in that region, Ridder, bore Philip Ridder's name from 1786 to 1941, when it was changed to Leninogorsk; however, in 2002, the name was reverted to Ridder. The town is notable as the eastern terminus of European route E40.