The Strait of Georgia or the Georgia Strait (also known as the Gulf of Georgia), is a strait between Vancouver Island (as well as its nearby Gulf Islands) and the mainland Pacific coast of British Columbia, Canada. It is approximately long and varies in width from 18.5 to 55 km (11.5 to 34 mi). Archipelagos and narrow channels mark each end of the Strait of Georgia, the Gulf Islands and San Juan Islands in the south, and the Discovery Islands in the north. The main channels to the south are Haro Strait and Rosario Strait, which connect the Strait of Georgia to the Strait of Juan de Fuca. In the north, Discovery Passage is the main channel connecting the Strait of Georgia to Johnstone Strait.
The USGS defines the southern boundary of the Strait of Georgia as a line running from East Point on Saturna Island to Patos Island, Sucia Island, and Matia Island, then to Point Migley on Lummi Island. This line touches the northern edges of Rosario Strait, which leads south to the Strait of Juan de Fuca, and Boundary Pass, which leads south to Haro Strait and the Strait of Juan de Fuca.
The mean depth of the Strait of Georgia is , with a maximum depth of . Its surface area is approximately . The Fraser River accounts for roughly 80% of the freshwater entering the strait. Water circulates in the strait in a general counter-clockwise direction.
The term "Gulf of Georgia" includes other waters than the Georgia Strait proper such as the interinsular straits and channels of the Gulf Islands, and as a region name may refer to communities on the littoral of southern Vancouver Island. As defined by George Vancouver in 1792, the Gulf of Georgia included all the inland waters beyond the eastern end of the Strait of Juan de Fuca, including Puget Sound, Bellingham Bay, the waters around the San Juan Islands, and the Strait of Georgia.
Towns and cities on the strait include Courtenay, Comox, Qualicum Beach, Parksville, Lantzville and Nanaimo on the western shore, as well as Powell River, Sechelt, Gibsons, and Greater Vancouver on the east. Across the border in the United States, Bellingham, Washington and other communities also lie on the eastern shore. Other settlements on Vancouver Island (such as Duncan) and the mainland are separated from Georgia Strait itself by islands, or are far enough south to be considered closer to Puget Sound.
In 1967, Georgia Strait inspired the name of Vancouver's alternative newspaper, The Georgia Straight, which has published continuously since.