The Pacific Time Zone (PT) is a time zone encompassing parts of western Canada, the western United States, and western Mexico. Places in this zone observe standard time by subtracting eight hours from Coordinated Universal Time (UTC−08:00). During daylight saving time, a time offset of UTC−07:00 is used.

In the United States and Canada, this time zone is generically called the Pacific Time Zone. Specifically, time in this zone is referred to as Pacific Standard Time (PST) when standard time is being observed (early November to mid-March), and Pacific Daylight Time (PDT) when daylight saving time (mid-March to early November) is being observed. In Mexico, the corresponding time zone is known as the Zona Noroeste (Northwest Zone) and observes the same daylight saving schedule as the United States and Canada. The largest city in the Pacific Time Zone is Los Angeles, whose metropolitan area is also the largest in the time zone.

The zone is two hours ahead of the Hawaii–Aleutian Time Zone, one hour ahead of the Alaska Time Zone, one hour behind the Mountain Time Zone, two hours behind the Central Time Zone, three hours behind the Eastern Time Zone, and four hours behind the Atlantic Time Zone.

One Canadian province is split between the Pacific Time Zone and the Mountain Time Zone:

The border between time zones in British Columbia was decided in a 1972 plebiscite held in northeastern and southeastern electoral districts due to their ties to neighbouring Alberta.

As of September 24, 2020, Yukon officially switched from the Pacific Time Zone to a time zone "to be reckoned as seven hours behind Coordinated Universal Time (UTC−7)" after deciding to stop observing daylight saving time.

In Mexico, the Zona Noroeste, which corresponds to Pacific Time in the United States and Canada, includes:^{[citation needed]}

Two states are fully contained in the Pacific Time Zone: