Ryan Day (born 23 March 1980) is a Welsh professional snooker player. As a prolific break-builder, he has compiled more than 350 century breaks during his career and one maximum break.
Day was born in Pontycymer, Bridgend, and began his professional career by playing UK Tour in 1998, at the time the second-level professional tour. He was named Young Player of Distinction of the season 2000/2001 by the World Professional Billiards and Snooker Association (WPBSA). He won the 2001 Benson & Hedges Championship. He also won the WPBSA Challenge Tour in the 2001/2002 season and was named WPBSA Newcomer of the Year in 2002.