Loch Restil is a freshwater loch that lies in the pass between Glen Croe and Glen Kinglas on the Cowal Peninsula, in Argyll and Bute, West of Scotland. One of the main roads to the west of Scotland coast, the A83, passes Loch Restil. The burn that flows from Loch Restil is one of the feeds of Kinglas Water, in Glen Kinglas, which flows under the Butter Bridge.