Isay () is an uninhabited island in the Inner Hebrides of the west coast of Scotland. It lies in Loch Dunvegan, off the northwest coast of the Isle of Skye. Two smaller isles of Mingay and Clett lie nearby. The name originated from the Old Norse ise-øy meaning porpoise island. The island of Lampay is due south. The area of Isay is .
The island was home to a small fishing community in around the 1830s, which included a general store and fishing station, and by 1841 supported 15 families "in considerable comfort". However, like many other small islands, the population of around ninety were removed during the Highland clearances to make way for sheep. The remains of the 18 or more cottages can be clearly seen from the Waternish peninsula, which overlooks the three islands.
The island was briefly owned by the singer Donovan in the 1960s.