Adopted in 1965 to replace the Union Flag, it is the first ever specified by statute law for use as the country's national flag. The Canadian Red Ensign had been unofficially used since the 1890s and was approved by a 1945 Order in Council for use "wherever place or occasion may make it desirable to fly a distinctive Canadian flag".

In 1964, Prime Minister Lester B. Pearson appointed a committee to resolve the issue, sparking a serious debate about a flag change. Out of three choices, the maple leaf design by George Stanley and John Matheson, based on the flag of the Royal Military College of Canada, was selected. The flag made its first official appearance on February 15, 1965; the date is now celebrated annually as National Flag of Canada Day.

Many different flags have been created for use by Canadian officials, government bodies, and military forces. Most of these flags contain the maple leaf motif in some fashion, either by having the Canadian flag charged in the canton, or by including maple leaves in the design. The Royal Union Flag is also an official flag in Canada.