Macrian or Makrian (Latin: Macrianus) was the king of the Bucinobantes, an Alemannic tribe, in the late fourth century and the brother of Hariobaudes.
According to Ammianus Marcellinus, In 359 Julian the Apostate took Mogontiacum (Mainz on the Rhine) and, after the exchange of prisoners, made treaties of peace with the various Alemanni kings, Macrian, Hariobaudes, Urius, Ursicinus, Vadomarius, and Vestralpus.
In his place was set up Fraomar, but the Bucinobantes would not accept him and he was expelled and Macrian restored.
In 371 Valentinian was forced to grant Macrian an alliance; the Bucinobantes became foederati of Rome and loyal allies in the war with the Franks.
Macrian was killed on campaign against the Franks, in an ambush laid by their king Mallobaudes.