Khmer people are the predominant ethnic group in Cambodia, accounting for approximately 90% of the 14.8 million people in the country. They speak the Khmer language, which is part of the larger Mon-Khmer language family found throughout Southeast Asia. The majority of the Khmer are followers of the Khmer style of Buddhism, a highly syncretic version which blends elements of Theravada Buddhism, Hinduism, animism and ancestor-spirit worship. Significant populations of Khmers reside in adjacent areas of Thailand (Northern Khmer) and the Mekong Delta region of neighboring Vietnam (Khmer Krom).
Excerpted from Wikipedia’s article on the Khmer Peoples