Dream Lake is a freshwater lake located on the southern slope of Dog Mountain in King County, Washington, United States. It is west of Otter Lake, part of the Alpine Lakes Wilderness. Big Creek, a tributary to the Taylor River, exits Dream Lake into a canyon that produces Big Creek Falls. Because of its proximity to Dog Mountain summit and the cirque of Rooster Mountain to the west, the lake is a popular area for hiking, swimming, and fishing and rainbow trout. Access to Dream Lake is provided through an unmaintained access trail that splits off the Snoqualmie Lake Trail.