| Lord Mayor Bay | |
| Location: | Western Gulf of Boothia |
| Coords: | 69.7333°N -94°W |
| Pushpin Map: | Canada Nunavut |
| Countries: | Canada |
| Cities: | Uninhabited |
Lord Mayor Bay is an Arctic waterway in Kitikmeot Region, Nunavut, Canada. It is located in the west of the Gulf of Boothia.
The bay is roughly diamond-shaped. To the north-east, the bay opens into the Gulf of Boothia; the Astronomical Society Islands lie in the bay's mouth. The Nunavut mainland surrounds the rest of the bay; to the north-west is the Boothia Peninsula.