The Group of Seven , also known as the Algonquin School, was a group of Canadian landscape painters from 1920 to 1933, originally consisting of Franklin Carmichael (1890–1945), Lawren Harris (1885–1970), A. Y. Jackson (1882–1974), Frank Johnston (1888–1949), Arthur Lismer (1885–1969), J. E. H. MacDonald (1873–1932), and Frederick Varley (1881–1969). Later, A. J. Casson (1898–1992) was invited to join in 1926; Edwin Holgate (1892–1977) became a member in 1930; and LeMoine FitzGerald (1890–1956) joined in 1932
Two artists commonly associated with the group are Tom Thomson (1877–1917) and Emily Carr (1871–1945). Although he died before its official formation, Thomson had a significant influence on the group. In his essay "The Story of the Group of Seven", Harris wrote that Thomson was "a part of the movement before we pinned a label on it"; Thomson's paintings The West Wind and The Jack Pine are two of the group's most iconic pieces.  Emily Carr was also closely associated with the Group of Seven, though was never an official member.
Believing that a distinct Canadian art could be developed through direct contact with nature, the Group of Seven is best known for its paintings inspired by the Canadian landscape, and initiated the first major Canadian national art movement.  The Group was succeeded by the Canadian Group of Painters in the 1933, which included members from the Beaver Hall Group who had a history of showing with the Group of Seven internationally. 
Large collections of work from the Group of Seven can be found at the Art Gallery of Ontario in Toronto, the National Gallery of Canada in Ottawa as well as the Ottawa Art Gallery (home to The Firestone Collection of Canadian Art) and the McMichael Canadian Art Collection in Kleinburg, Ontario. The National Gallery, under the directorship of Eric Brown, was an early institutional supporter of artists associated with the Group, purchasing art from some of their early exhibitions before they had identified themselves officially as the Group of Seven.  The Art Gallery of Ontario, in its earlier incarnation as the Art Gallery of Toronto, was the site of their first exhibition as the Group of Seven.  The McMichael was founded by Robert and Signe McMichael, who began collecting paintings by the Group of Seven and their contemporaries in 1955.
Tom Thomson, J. E. H. MacDonald, Arthur Lismer, Frederick Varley, Frank Johnston and Franklin Carmichael met as employees of the design firm Grip Ltd. in Toronto. In 1913, they were joined by A. Y. (Alexander Young) Jackson and Lawren Harris. They often met at the Arts and Letters Club of Toronto to discuss their opinions and share their art. 
This group received monetary support from Harris (heir to the Massey-Harris farm machinery fortune) and Dr. James MacCallum. Harris and MacCallum jointly built the Studio Building in 1914 in the Rosedale ravine to serve as a meeting and working place for the new Canadian art movement. MacCallum owned land on Georgian Bay and Thomson worked as a guide in nearby Algonquin Park, both places where he and the other artists often travelled for inspiration. 
The informal group was temporarily split up during World War I, during which Jackson and Varley became official war artists. A further blow to the group came in 1917 when Thomson died while canoeing in Algonquin Park. He appeared to have suffered a blow to the head and showed no signs of drowning. The circumstances of his death remain mysterious. 
The seven who formed the original group reunited after the war. They continued to travel throughout Ontario, especially the Muskoka and Algoma regions, sketching the landscape and developing techniques to represent it in art. In 1919, they decided to make themselves into a group devoted to a distinct Canadian form of art which didn't exist yet, and began to call themselves the Group of Seven.  It is unknown who specifically chose these seven men, but it is believed to have been Harris. By 1920, they were ready for their first exhibition thanks to the constant support and encouragement of Eric Brown, the director of the National Gallery at that time. Prior to this, many artists believed the Canadian landscape was not worthy of being painted. Reviews for the 1920 exhibition were mixed, but as the decade progressed the Group came to be recognized as pioneers of a new, Canadian, school of art.
After Frank Johnston left the group in 1920 to move to Winnipeg, A. J. Casson was invited to join in 1926.  Franklin Carmichael had taken a liking to him and had encouraged Casson to sketch and paint for many years beforehand.
The members of the Group began to travel elsewhere in Canada for inspiration, including British Columbia, Quebec, Nova Scotia, and the Arctic. After Samuel Gurney Cresswell and other painters on Royal Navy expeditions, these were the first artists of European descent who depicted the Arctic. Soon, the Group made the decision that to be called a "national school of painters" there should be members from outside Toronto. So, in 1930, Edwin Holgate from Montreal, Quebec became a member and in 1932, also LeMoine Fitzgerald from Winnipeg, Manitoba. 
The Group's influence was so widespread by the end of 1931, and after J.E.H. MacDonald's death in 1932, they no longer found it necessary to continue as a group of painters. They announced that the Group had been disbanded and that a new association of painters would be formed, known as the Canadian Group of Painters. The Canadian Group—which eventually consisted of the majority of Canada's leading artists—held its first exhibition in 1933, and continued to hold exhibitions almost every year as a successful society until 1967.
The Group of Seven has received criticism for its reinforcement of terra nullius presenting the region as pristine and untouched by humans when in fact the areas depicted have been lived in for many centuries. 
In 1995, the National Gallery of Canada compiled a Group of Seven retrospective show, for which they commissioned the Canadian rock band Rheostatics to write a musical score. That score was released on album as Music Inspired by the Group of Seven .
Six members of the group, A.Y. Jackson,  Arthur Lismer,  Frederick Varley,  Lawren Harris,  Frank Johnston,  and A.J. Casson  along with four of the artists' wives are buried onsite at the McMichael Canadian Art Collection in the small patch of consecrated land bordered by trees, with graves marked by large chunks of the Canadian Shield.
Contemporary painter Rae Johnson has derived much of her style from the Group of Seven. 
On 18 September 1970 Canada Post issued 'The Group of Seven' designed by Allan Robb Fleming based on a painting "Isles of Spruce" (1922) by Arthur Lismer in the Hart House Permanent Collection, University of Toronto. The 6¢ stamps are perforated 11 and were printed by Ashton-Potter Limited. 
On 29 June 1995, Canada Post issued 10 stamps, each based on a painting of each member of the group (7 original members and 3 new members):
- Francis Hans Johnston, Serenity, Lake of the Woods 
- Arthur Lismer, A September Gale, Georgian Bay 
- James Edward Hervey MacDonald, Falls, Montreal River 
- Frederick Horsman Varley, Open Window 
- Franklin Carmichael, October Gold 
- Lawren Stewart Harris, North of Lake Superior 
- Alexander Young Jackson, Evening, Les Éboulements 
- Alfred Joseph Casson, Mill Houses 
- Lionel LeMoine FitzGerald, Pembina Valley 
- Edwin Headley Holgate, The Lumberjack 
On year 2012–2013, Royal Canadian Mint issued 7 pure silver 1-oz coins, each one reproduced one painting of a member: 
- F.H. Varley Stormy Weather, Georgian Bay (April 2012) 
- Arthur Lismer Nova Scotia Fishing Village (July 2012) 
- Franklin Carmichael Houses, Cobalt (October 2012) 
- Lawren S. Harris Toronto Street, Winter Morning (January 2013) 
- Franz Johnston The Guardian of the Gorge (March 2013) 
- J.E.H. MacDonald Sumacs (June 2013)
- A.Y. Jackson Saint-Tite-des-Caps (September 2013)