Tridrepana mediata is a moth in the Drepanidae family. It was described by Warren in 1922. It is found in New Guinea, extending to Goodenough Island and Sudest Island in the south-west. The wingspan is about 29.4-33.4 mm for males and 34.2-42.2 mm for females. Adults are similar to Tridrepana albonotata, but can be distinguished by the dark brown colour of the male and the paler brown colour of the female.