千岛群岛（Thousand Islands），又称千岛湖，位于北美洲圣劳伦斯河与安大略湖的交汇处，是一个拥有1865个小岛的景点，分属加拿大、美国两国。

湖中的小岛大的有100km²，小的只有几块礁石。有些岛上有建筑物，比较著名的是Boldt城堡。游人一般从加拿大的京士顿、Gananoque或美国纽约州的Clayton坐船前往。

The Thousand Islands constitute an archipelago of 1,864 islands that straddles the Canada-U.S. border in the Saint Lawrence River as it emerges from the northeast corner of Lake Ontario. They stretch for about 50 miles (80 km) downstream from Kingston, Ontario. The Canadian islands are in the province of Ontario, the U.S. islands in the state of New York. Canada is home to the majority of islands with just over two-thirds in Ontario.