Douglas George Grimston (May 18, 1900 – September 14, 1955) was a Canadian ice hockey administrator who served as president of the Canadian Amateur Hockey Association (CAHA) from 1950 to 1952. He oversaw the establishment of the Major Series for the Alexander Cup and implemented a new deal for player contracts in senior ice hockey, in response to the Allan Cup championship being dominated by a small group of teams who sought to protect themselves from professional leagues recruiting their players. He opposed the National Hockey League wanting its junior ice hockey prospect players on stronger teams, which led to limits on the transfer of players to keep balanced competition for the Memorial Cup. After the 1952 Winter Olympics where the Canada men's national ice hockey team won the gold medal, Grimston recommended withdrawal from Olympic hockey since European nations would never agree to ice hockey rules which allowed physical play. Grimston later accused International Ice Hockey Federation vice-president Bunny Ahearne of financially exploiting of the Edmonton Mercurys on a European tour, which led to a physical altercation between them.

Grimston served as president of the British Columbia Amateur Hockey Association from 1942 to 1947, and was credited by The Canadian Press for keeping junior ice hockey operational despite the lack of facilities and dwindling attendance during World War II. He also sat on the national committee to oversee minor ice hockey in Canada, and sought for the transparency of finances in amateur hockey. He served as a director for the New Westminster Royals and played a leading role in their successful bid to join the Western Hockey League in 1952. He was a vocal supporter of the Penticton Vees and led a committee to oversee travel arrangements for the team as it won the 1955 Ice Hockey World Championships for Canada. He was a member of multiple community service groups, served four terms as chairman of the New Westminster Parks Commission and was president of the local Rotary Club. He sought for the construction of the Queen's Park Stadium and to expand and beautify city parks. Grimston died in 1955 at age 55, was posthumously recognized by New Westminster with Grimston Park named in his honour the same year, and was described by Jimmy Dunn as "one of the most colourful and aggressive presidents the CAHA ever had".

Douglas George Grimston was born on May 18, 1900, in New Westminster, British Columbia. He was the son of George Grimston and Jean McCormack, both of whom were Protestants from England. Grimston played baseball, soccer and lacrosse as a youth. He was a member of the British Columbia Manufacturing Company baseball team who were the New Westminster city champions in 1920 and 1923, and was a member of the Sapperton AFC team who won the second division and the Lower Mainland Cup championship during the 1923 and 1924 soccer seasons.

Grimston married schoolteacher Marjorie Evelyn Gilley on September 5, 1928, in New Westminster. They had one son and three daughters, and were married until her death on October 4, 1952.

Grimston worked for Westminster Ice Limited, a trucking company which delivered ice and was owned by his father. Grimston later worked at Westminster Hog Fuels for 25 years and was a managing director for the company. He was a member of the local Masonic lodge and the Elks of Canada; and served as a president of the New Westminster Rotary Club, the junior board of trade in New Westminster, and the Vancouver Golf Club.

Grimston was a director for the New Westminster Royals, and insisted on the continuation of a smoking ban at the Queen's Park Arena. Despite criticism by the local parks commissioner that the ban had a negative effect on attendance, Grimston indicated that he would take financial responsibility for lost attendance. He also served as president of the New Westminster Athletic Association, and played a leading role in a successful bid by the Royals to join the Western Hockey League in 1952. He later served four terms as chairman of the New Westminster Parks Commission. He sought to expand and beautify parks in the city, and for the construction of the Queen's Park Stadium. He was defeated for re-election to the commission in 1954.

Grimston first joined to the British Columbia Amateur Hockey Association (BCAHA) executive in 1938, and was elected its vice-president in 1941. Following the attack on Pearl Harbor, he announced the cancellation of games until the end of blackout orders along the coast of the Pacific Ocean, and hoped to resume games with adjustments made for the blackout.

In 1941, Grimston predicted the collapse of senior ice hockey in the province due to rumours that sponsors from the British Columbia Interior were tired of supporting expensive amateur teams, and that the Kimberley Dynamiters and the Trail Smoke Eaters would drop down to the lower intermediate level classification to save money. The Trail Daily Times denied the rumors and stated a desire to remain at the top level and be eligible for the Allan Cup. The teams played in the West Kootenay League which subsequently suspended operations in 1941 due to World War II.