National Flag of Canada Day is observed on February 15, 2021. Flag Day, officially named National Flag of Canada Day, commemorates the inauguration of the Flag of Canada on that date in 1965. The day is marked by flying the flag, occasional public ceremonies, and educational programs in schools. It is not a public holiday, although there has been discussion about creating one.
The Maple Leaf flag replaced the Canadian Red Ensign, which had been, with various successive alterations, in conventional use as a Canadian national flag since 1868. Under the leadership of Prime Minister Lester Pearson, resolutions recommending the new flag were passed by the House of Commons on December 15, 1964, and by the Senate two days later. The flag was proclaimed by Elizabeth II, Queen of Canada, on January 28, 1965, and took effect "upon, from and after" February 15.
National Flag of Canada Day was instituted in 1996 by an Order in Council from Governor General Roméo LeBlanc, on the initiative of Prime Minister Jean Chrétien. It was decided National Flag Day would not be an acceptable name for the date, given the multiple uses of the word "nation" or "national" in Canada. The resulting inclusion of the words "of Canada" disambiguated exactly what nation was being referred to, but created a title that could be interpreted as suggesting there is a national flag for Canada Day. (With material from: Wikipedia)