Kampong Thom (Khmer: កំពង់ធំ) is a province of Cambodia. It borders the provinces of Siem Reap to the northwest, Preah Vihear to the north, Stung Treng to the northeast, Kratie to the east, Kampong Cham, Kampong Chhnang to the south, and the Tonle Sap to the west.
The provincial capital is Kampong Thom City, a town of approximately 30,000 people on the banks of the Stung Sen River.
Kampong Thom is Cambodia's second largest province by area. There are a number of significant Angkorian sites in the area, including Prasat Sambor Prei Kuk and Prasat Andet temples. As one of the nine provinces bordering Tonle Sap Lake, Kampong Thom is part of the Tonlé Sap Biosphere Reserve.