Davud of Merv (died 1221) was the Khwarazmian governor of Merv during the 13th century. In 1221, he defended the city against Tolui Khan's Mongol army at the Siege of Merv, and, after a week-long siege, he agreed to surrender in exchange for mercy. However, Tolui had all of the inhabitants - including Davud - massacred in a war crime even worse than the recent Siege of Urgench.