HTMS Sri Ayudhya (Thai: เรือหลวงศรีอยุธยา, RTGS: Si Ayutthaya) was a coastal defence ship of the Royal Thai Navy. It was in service from 1938 to 1951, being active during the Franco-Thai war in which its sister ship HTMS Thonburi was heavily damaged in the Battle of Ko Chang. Sri Ayudhya later served as flagship of the navy until it was sunk as a result of fighting in the Manhattan Rebellion.