Urbain Jean Joseph Le Verrier (March 11, 1811 – September 23, 1877) was a French mathematician who specialized in celestial mechanics. He worked at the Paris Observatory for most of his life.

He was born in Saint-Lô, France.

His most famous achievement is the discovery of Neptune, using only mathematics and astronomical observations. Encouraged by Arago [1], he performed calculations to explain discrepancies between Uranus's observed orbit and that predicted from the laws of Kepler and Newton. At the same time, but unknown to each other, the same calculations were made by Adams. Le Verrier assisted Galle in locating the planet (September 1846); which was found within 1° of its predicted location at a point in Aquarius. (There was, and to some extent still is, some controversy over the apportionment of credit for the discovery; see Discovery of Neptune.)

Perhaps galvanized by his discovery, Le Verrier proceeded to interpret the orbit of Mercury as influenced by another planet (tentatively named Vulcan). This triggered a wave of false detections, which lasted until 1915, when Einstein explained the anomalous motion with his theory of general relativity.

He won the Gold Medal of the Royal Astronomical Society in 1868 and again in 1876.

He died in Paris, France.

Craters on the Moon and Mars, a ring of Neptune, and the asteroid 1997 Leverrier are named after him.