River Shira () is the river that runs for about 7 miles through Glen Shira, in Argyll and Bute, west of Scotland. Originating to the north-east at altitude, near the start of the River Fyne.
The river runs into the Lochan Shira reservoir, feeding the 5 MW (Big Nose), Shira Hydro-Electric Scheme, at altitude and dropping . The river includes a few waterfalls and islands, including (The Island of Fear).
The River Shira flows into Loch Dubh (Black Lake), where the Ancient Clan MacNaghten castle and crannogs used to be situated, then passes Stuart Liddell's house. Loch Dubh drains through the short (River Garron), then flows under the Garron Bridge into Loch Fyne, a sea loch.
The river lends its name to the ferry .