Flag of Ontario, Canada The Flag of Ontario is the official banner representing the Canadian province of Ontario. Adopted on February 15, 1965, it is a white field with a red maple leaf in its center, surrounded by three white maple tree seedlings arranged in a triangular formation to the left of the leaf. The flag's design symbolizes the growth and progress of Ontario. The colors red and white are significant as they are also found in the Canadian national flag. The flag serves as a visual emblem for the province, often used during ceremonial events, public gatherings, and official functions.