Alan William James Cousins FRAS (8 August 1903 – 11 May 2001) was a South African astronomer. His career spanned 70 years during which time he concentrated on the measurement of variable stars, including the measurement of the two sinusoidal periods of Gamma Doradus. The UBV photometric system for measuring stellar fluxes he devised in his 1990s became a standard known as the "Cousins system".