Not to be confused with either the Douglas Water which flows into Loch Fyne or the Douglas Water which flows into the Clyde
Glen Douglas (Scottish Gaelic: Gleann Dùghlais) is a glen in the southwest Scottish Highlands. It is drained by the Douglas Water which discharges at the village of Inverbeg at its eastern end into Loch Lomond. The glen is followed by a minor road which links the A82 road alongside Loch Lomond with the A814 road beside Loch Long. The glen is overlooked to the north by Beinn Bhreac (681m) and Tullich Hill (632m) and to the south by Doune Hill (700m) and a 655m hill known as Coire na h-Eanachan.
At the upper (western) end of the glen is the DM Glen Douglas military munitions depot which is connected to the railway line from Helensburgh to Crianlarich.