William Ashby (born 12 January 1786 at Linton, Kent; died 10 April 1847 at Lambeth) was an English cricketer in the 19th century. He played mainly for Kent and was an outstanding slow bowler, probably underarm but he may have bowled roundarm in the later years of his career. It is unknown if he was right-handed or left-handed.
Ashby made his known debut in the 1808 season and had 45 known appearances in major matches to the 1830 season. He took a known 164 wickets (bowled only) with a best tally of 8 in one innings. Being a specialist bowler, he was a modest batsman and made only 242 runs @ 4.48 with a highest score of 18.