| Honorific-Prefix: | The Honourable |
| Walter Edward Foster | |
| Order: | 17th Premier of New Brunswick |
| Term Start: | April 4, 1917 |
| Term End: | February 1, 1923 |
| Predecessor: | James A. Murray |
| Successor: | Peter J. Veniot |
| Lieutenant Governor: | Josiah Wood Gilbert White Ganong William Pugsley |
| Office1: | MLA for Victoria |
| Term Start1: | April 23, 1917 |
| Term End1: | October 9, 1920 |
| Successor1: | George W. Warnock |
| Alongside1: | John F. Tweeddale |
| Office2: | MLA for Saint John City |
| Term Start2: | October 9, 1920 |
| Term End2: | February 1, 1923 |
| Predecessor2: | John R. Campbell |
| Successor2: | Leonard P. D. Tilley |
| Alongside2: | Robert T. Hayes, William E. Scully, W. F. Roberts |
| Office3: | Secretary of State for Canada |
| Primeminister3: | W. L. Mackenzie King |
| Term Start3: | September 26, 1925 |
| Term End3: | November 12, 1925 |
| Predecessor3: | Arthur Bliss Copp |
| Office4: | Speaker of the Senate of Canada |
| Primeminister4: | W. L. Mackenzie King |
| Term Start4: | January 11, 1936 |
| Term End4: | May 8, 1940 |
| Predecessor4: | Pierre-Édouard Blondin |
| Successor4: | Georges Parent |
| Office5: | Senator for Saint John, New Brunswick |
| Nominator5: | W. L. Mackenzie King |
| Appointer5: | The Marquess of Willingdon |
| Term Start5: | December 6, 1928 |
| Term End5: | November 14, 1947 |
| Birth Date: | April 9, 1873 |
| Birth Place: | St. Martins, New Brunswick, Canada |
| Death Place: | Saint John, New Brunswick, Canada |
| Party: | New Brunswick Liberal Association Liberal Party of Canada |
| Children: | Walter W. V. Foster |
| Occupation: | Businessman |
| Profession: | Politician |
Walter Edward Foster (April 9, 1873 – November 14, 1947) was a Canadian politician and businessman in New Brunswick.
Foster was born in St. Martins, New Brunswick. He began work as a clerk with the Bank of New Brunswick at Saint John. He joined the merchant firm of Vassie and Company and became vice president and managing director after marrying Johanna Vassie, daughter of the firm's head. Active in community business affairs, Foster served as President of the Saint John Board of Trade in 1908–1909.
In 1916, Walter Foster became leader of the province's Liberal Party which swept to victory in the 1917 election. Foster was defeated in the Saint John County riding in the 1917 election but was elected to the Legislative Assembly by acclamation in a by-election later that year in Victoria County. Though leader at age 45, he was called the "boy premier" for his youthful, cleancut appearance (Doyle). His government established the first department of health in 1918, gave women the right to vote in 1919 and created the province's power commission in 1920.
Walter Foster resigned from provincial politics on February 1, 1923 in order to return to put his own failing personal finances in order. He entered federal politics becoming Secretary of State of Canada in 1925, but failed to win a seat in that year's federal election.
In 1928, Walter Foster was appointed by Prime Minister Mackenzie King to the Senate of Canada and served as Speaker of the Senate of Canada from 1936 to 1940.
Foster married Joanna Vassie in 1903. His son, Walter William Vassie Foster, served in the provincial Legislative Assembly.
He died in office in Saint John at the age of 74 and was buried in the Cedar Hill Cemetery.