Oliver Payne Pearson (October 21, 1915 in Philadelphia, Pennsylvania – March 4, 2003 in Walnut Creek, California), or "Paynie" to many that knew him, was an American zoologist and ecologist.

Pearson is best known for his work on the role of predation on vole demography and population cycles, and for his piercing contributions to the biology of South American mammals, but his earlier studies on reproductive and physiological ecology are highly regarded as well.

In 1957 he resigned his tenured position, maintaining status at UC Berkeley as a lecturer in zoology and as a research associate at the museum.

This allowed him to focus his attentions on his studies of voles and predation, and to spend a year as a visiting professor of ecology at the University of Buenos Aires (1964–65).

When awarded an honorary doctoral degree ("Doctor Honoris Causa") from the University of La Plata, Argentina in 2000, Pearson famously stated "Yo soy un simple atrapador de ratones, y nada hubiese sido posible sin Anita" ("I am a simple mouse-trapper, and nothing would have been possible without Anita").