Henry Nicholas Ridley CMG (1911), MA (Oxon), FRS, FLS, F.R.H.S. was an English botanist, geologist and naturalist who lived much of his life in Singapore. He was instrumental in promoting rubber trees in the Malay Peninsula and, for the fervour with which he pursued it, came to be known as "Mad Ridley".

Amphisbaena ridleyi, known by the common names Ridley's worm lizard or the Noronha worm lizard, is a species of amphisbaenian in the family Amphisbaenidae. The species is endemic to the island of Fernando de Noronha off the coast of Brazil. It is one of two indigenous reptiles on the island.