Värmdö is an island in the innermost region of the Stockholm archipelago and covers an area of 180 km², making it the largest island in the archipelago. Värmdö is after Gotland and Öland the third largest island on the eastern coast of Sweden.
Värmdö lies in Stockholm County. Most of it forms part of Värmdö Municipality along with other islands, but the western end is part of Nacka Municipality, which lies mostly on the mainland, to which it is connected by a road bridge.
The UK-based Swedish television presenter Ulrika Jonsson has a home on the island.