| Fountain of Neptune | |
| Other Language 1: | Spanish |
| Other Title 1: | Fuente de Neptuno |
| Artist: | Juan Pascual de Mena |
| Year: | 1781–1786 |
| Medium: | White marble |
| Movement: | Neoclassicism |
| Subject: | Neptune |
| Metric Unit: | cm |
| Imperial Unit: | in |
| City: | , Madrid, Spain |
| Coordinates: | 40.4153°N -3.6942°W |
The Fountain of Neptune (Spanish: Fuente de Neptuno) is a neoclassical fountain located in Madrid, Spain. It lies on the centre of the, a roundabout in the Paseo del Prado. The sculptural group in its centre represents Neptune, a Roman water deity.
Designed by Ventura Rodríguez, the sculpture—made of white marble from Montesclaros—was commissioned to Juan Pascual de Mena. Sculptural works began in 1781. Following the master's death in April 1784, the fountain was finished in October 1786 by his disciples.
The fountain is formed by a circular pylon with the sculptural group in its centre. The crowned Roman god wields a trident with one hand while he grabs a sea snake with the other hand.
It has a maximum water capacity of 305 m3.
The fountain is the site where the Atlético Madrid's fans celebrate the team's trophies.