Valley Metro Bus is a transit bus system for public transport in Maricopa County, Arizona, United States. In 2023, the system had a ridership of 24,215,700, or about 85,000 per weekday as of the fourth quarter of 2023. Buses are operated by private companies contracted by Valley Metro and the City of Phoenix. Service currently operates throughout the broader Phoenix Metropolitan Area. All buses have wheelchair ramps or lifts, and except for paratransit vehicles, all buses have bike racks.

The Valley Metro Regional Public Transportation Authority, more popularly known as Valley Metro, is the unified public brand of the regional transit system for the Phoenix metropolitan area. Within the system, it is divided between Valley Metro Bus, which runs all bus operations, Valley Metro Rail, which is responsible for light rail and streetcar operations in the Valley. In 2023, the combined bus and rail system had a ridership of 36,374,000, or about 122,500 per weekday as of the fourth quarter of 2023.