Sihanoukville (Khmer: ក្រុងព្រះសីហនុ - Krong Preah Sihanouk), also known as Kampong Saom, is a province (khaet) of Cambodia on the Gulf of Thailand. This port city is a growing Cambodian urban center, located 185 kilometres (115 mi) southwest of the Cambodian capital, Phnom Penh. The province is named after King Father Norodom Sihanouk and grew up around the construction of Sihanoukville Port. Construction on the port began in June 1955 and it was the only deep water port in Cambodia. The port was built in part due to the waning power of the French leading to the Vietnamese tightening their control over the Mekong Delta and hence restricting river access to Cambodia. Sihanoukville's beaches have made it a popular tourist destination.

The province is served by Sihanoukville International Airport, 18 kilometres (11 mi) from downtown, although it has a limited commercial operation. The planned flights between Sihanoukville and Siem Reap may encourage visitors to Angkor temples in Siem Reap to extend their stay, though the crash of a charter flight in Phnom Damrey on 25 June 2007 from Siem Reap, has caused concerns. The flights are scheduled to start on December 14, 2011.