Luna Island is a very small uninhabited island in Niagara Falls, New York. It is between the American Falls and Bridal Veil Falls, which are two of the waterfalls that make up Niagara Falls. It is approximately 130 feet wide (between the two falls) and 350 feet long (extending upstream from the falls).

The island is said to derive its name from the ability of an observer, when standing on the island during a full moon, to see "lunar rainbows" in the Niagara mist.

Spectators can view the falls from Goat Island and Luna Island, which are accessible by pedestrian bridges that cross the rapids of the Niagara river upstream from the falls. Spectators on Luna Island can stand a few feet away from both Bridal Veil Falls and American Falls by walking across the island. Representatives of the nearby Schoelkopf Geological Museum often come to Luna Island where they bring photographs and answer questions about Niagara Falls.