A framed painting by Tom Thomson entitled "Northern Lights".

Thomas John Thomson (August 5, 1877 to July 8, 1917) was an influential Canadian artist of the early 20th century. He directly influenced a group of Canadian painters that would come to be known as the Group of Seven, and though he died before they formally formed, he is sometimes incorrectly credited as being a member of the group itself. Thomson died under mysterious circumstances, which added to his mystique. In 1907, Thomson joined Grip Ltd., an artistic design firm in Toronto, where many of the future members of the Group of Seven also worked. Since his death, Thomson's work has grown in value and popularity. In 2002, the National Gallery of Canada staged a major exhibition of his work, giving Thomson the same level of prominence afforded Picasso, Renoir, and the Group of Seven in previous years.