The Justiciar of Scotia (in Norman-Latin, Justiciarus Scotie) was the most senior legal office in the High Medieval Kingdom of Scotland. Scotia (meaning Scotland) in this context refers to Scotland to the north of the River Forth and River Clyde. The other Justiciar positions were the Justiciar of Lothian and the Justiciar of Galloway.
The institution has some Anglo-Norman origins, but in Scotland north of the Forth it represented some form of continuity with an older office, a senior version of a Judex or Brithem, a native Scottish lawman often with province-wide responsibilities. Mormaer Causantín of Fife was styled judex magnus (i.e. "great Brehon") in Scotia, and it is probable that the Justiciarship of Scotia was just a further Latinisation/Normanisation of that position. By the middle of the thirteenth century, the responsibilities of the Justiciar became fully formalised. He supervised the activity and behaviour of royal sheriffs and sergeants, held courts and reported on these things to the king personally.