Vesto Melvin Slipher (November 11, 1875 – November 8, 1969) was an American astronomer. His brother Earl C. Slipher was also an astronomer.

Slipher was born in Mulberry, Indiana, and completed his education at Indiana University. He spent his entire career at Lowell Observatory in Flagstaff, Arizona, where he was director from 1916 to 1952. He used spectroscopy to investigate the rotation periods of planets, the composition of planetary atmospheres, and was the first to observe the radial velocities of galaxies.

He won the Henry Draper Medal in 1932, the Gold Medal of the Royal Astronomical Society in 1933, and the Bruce Medal in 1935. Craters on Mars and the Moon are named in his honor.

He died in Flagstaff, Arizona.