Ma Dai () ( 222–235) was a Chinese military general of the state of Shu Han during the Three Kingdoms period of China. He previously served under his uncle Ma Teng, a warlord in northwestern China, during the late Eastern Han dynasty. After Ma Teng's death, he followed his cousin Ma Chao (Ma Teng's eldest son) and they joined the warlord Zhang Lu in Hanzhong for a short period of time. Ma Chao later defected to another warlord Liu Bei, and Ma Dai accompanied him. Ma Dai served under Liu Bei and later in the state of Shu Han (founded by Liu Bei). Not much information on Ma Dai is found in historical records. It is known that in 234, he participated in the fifth Northern Expedition led by Shu's chancellor Zhuge Liang to attack the Shu's rival state Cao Wei. Ma Dai was also credited with slaying the Shu general Wei Yan, who was alleged to have turned against Shu after the death of Zhuge Liang. Life Ma Dai was a younger cousin of Ma Chao. He does not have a biography in the Records of the Three Kingdoms (Sanguozhi), the authoritative source for the history of the Three Kingdoms period; he is mentioned occasionally in the biographies of other people such as Ma Chao and Wei Yan. He is first mentioned in Ma Chao's biography in a letter written by Ma Chao to Liu Bei before his death. Ma Chao wrote: "Over 200 members of my family were killed by Cao Cao. I only have my cousin Ma Dai left with me. He will be the one to continue my family line. I entrust him to Your Majesty's care. That is all I have to say." Ma Dai served in the state of Shu Han as a military general. The highest position he attained was "General Who Pacifies the North" (平北將軍). He was also enfeoffed as the "Marquis of Chencang" (陳倉侯). Ma Dai is mentioned in Wei Yan's biography. In 234, when conflict broke out between Yang Yi and Wei Yan after Zhuge Liang's death, Yang Yi ordered Ma Dai to attack Wei Yan. Ma Dai caught up with Wei Yan while the latter was fleeing towards Hanzhong, decapitated him, brought his head back, and threw it in front of Yang Yi. Ma Dai is also briefly mentioned in Sima Yi's biography in the Book of Jin. In