The River Garry (Scottish Gaelic: Gar / Abhainn Ghar) is a major tributary of the River Tummel, itself a tributary of the River Tay, in the traditional county of Perthshire in the Scottish Highlands. It emerges from the northeastern end of Loch Garry (56°49′09″N 4°13′52″W / 56.8193°N 4.2311°W), just to the southeast of the Pass of Drumochter, and flows southeastwards and eastwards down Glen Garry to the narrow Pass of Killiecrankie beyond which it joins the Tummel (56°43′06″N 3°46′44″W / 56.7182°N 3.7790°W).
Loch Garry itself is fed by the Allt Shallainn, Allt na Duinish and Allt na Cosaig which enter its southern end. The loch occupies a deep northeast-southwest aligned trench cut by glacial action. Glen Garry provides the main route northwards for both the A9 road and the railway from Perth to Inverness.