Marcus Metilius Aquillius Regulus (his recorded full name is Marcus Metilius Aquillius Regulus Nepos Volusius Torquatus Fronto) was a Roman senator of the second century AD. A member of the patrician order, he held the office of consul ordinarius in 157 with another patrician, Marcus Vettulenus Civica Barbarus, as his colleague.^[1]

The Metilii were an Italian family, likely from Transpadana.^[2] Regulus himself was the son of Publius Metilius Secundus, suffect consul in 123.^[3] Olli Salomies, in his study of the naming practices of the first centuries of the Roman Empire, notes that it "seems plausible enough" to infer his mother was a member of the gens Aquillia, and suggests that his praenomen was inherited from that side of the family.^[4]

His career began in his teens with the Vigintiviri, as one of the tresviri monetalis;^[5] assignment to this board was usually allocated to patricians or favored individuals.^[6] This was followed at 25 by a posting as quaestor, then at 30 as praetor. By the age of 32 or 33 Regulus was appointed consul, the usual age for patricians.^[7] Regulus is known to have held the priestly offices in the sodales Flaviales, the Salii collini, and in the collegium of augurs.^[5]