Arlo Udell Landolt (born September 29, 1935) is an American astronomer.
Landolt has worked principally in photometry and has published a number of widely used lists of standard stars.
In 1995, he received the George van Biesbroeck Prize from the American Astronomical Society.
Landolt was the first discoverer of a pulsating white dwarf when he observed in 1965 and 1966 that the luminosity of HL Tau 76 varied with a period of approximately 12.5 minutes.