Canada is divided into six time zones: Pacific, Mountain, Central, Eastern, Atlantic and Newfoundland time. Most areas of the country's provinces and territories operate on standard time from the first Sunday in November to the second Sunday in March and daylight saving time the rest of the year.

The divisions between time zones are based on proposals by Scottish Canadian railway engineer Sandford Fleming, who pioneered the use of the 24-hour clock, the world's time zone system, and a standard prime meridian.

The National Research Council (NRC) maintains Canada's official time through the use of atomic clocks. The official time is specified in legislation passed by the individual provinces. In Quebec it is based on coordinated universal time. The other provinces use mean solar time. The NRC provides both coordinated universal time and mean solar time in its signals. It makes time servers available for direct synchronization with computers. The Canadian Broadcasting Corporation aired a daily time signal, the National Research Council Time Signal, beginning 5 November 1939. The signal was discontinued on 15 October 2023.

The Government of Canada recommends use of the 24-hour clock (e.g. 18:33), which is widely used in contexts such as transportation schedules, parking meters, and data transmission. Speakers of Canadian French predominantly use this system, but most Canadian English speakers use the 12-hour clock in everyday speech (e.g. 6:33 pm), even when reading from a 24-hour display, similar to the use of the 24-hour clock in the United Kingdom.

Pacific Standard Time (PST) UTC−08:00 and Pacific Daylight Time (PDT) UTC−07:00:

Mountain Standard Time (MST) UTC−07:00 and Mountain Daylight Time (MDT) UTC−06:00:

Mountain Standard Time (MST) UTC−07:00 year-round:

Central Standard Time (CST) UTC−06:00 and Central Daylight Time CDT UTC−05:00: