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. 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. The asteroid 15072 Landolt is named after him.