Paul Greengard (December 11, 1925 – April 13, 2019) was an American neuroscientist best known for his work on the molecular and cellular function of neurons.

In 2000, Greengard, Arvid Carlsson and Eric Kandel were awarded the Nobel Prize for Physiology or Medicine for their discoveries concerning signal transduction in the nervous system.

[5] During World War II, he served in the United States Navy as an electronics technician at the Massachusetts Institute of Technology working on an early warning system against Japanese kamikaze planes.

Inspired by a lecture by Alan Hodgkin, Greengard began work on the molecular and cellular function of neurons.

Specifically, Greengard and his fellow researchers studied the behavior of second messenger cascades that transform the docking of a neurotransmitter with a receptor into permanent changes in the neuron.

He shared the 2000 Nobel Prize in Physiology or Medicine with Arvid Carlsson and Eric Kandel for his work on the central regulatory protein DARPP-32.

[13] In February 2018, a federal jury in the Southern District of New York found The Rockefeller University liable for discrimination based on race and national origin that occurred in 2007 in the lab of, and under the supervision of, Greengard.