Peter John Grubb is a British ecologist and emeritus professor of botany at Cambridge University. He took his Ph.D. at Cambridge University in 1960 supervised by G.E. Briggs. He subsequently joined the staff of Magdalene College, later becoming a full professor (retired in 2001). His early work was mentored by E.J.H. Corner and A.S. Watt, and especially influenced by the latter. He has written a very lively account on his becoming a plant ecologist.
Grubb has worked on diverse botanical and ecological subjects, from physiology to biomes and from chalk grassland to tropical rain forest. His name is particularly associated with the concept of regeneration niche.