Sachchidanand Sahai (6 March 1941, Bihar, India) is an Indian epigraphist, scholar and writer who wrote several essays on Angkorean civilization, and served as scientific advisor to the Government of Cambodia for the restoration of Angkor Wat and the Temple of Preah Vihear. His study on the latter temple (2009) helped to secure its inscription on UNESCO World Heritage List.
After studying Indian history, culture and archeology at Banares Hindu University, Varanasi, he presented his doctoral thesis under the guidance of George Coedes at Sorbonne University in 1969 (Les Institutions politiques et l'organisation administrative du Cambodge ancien). He then taught in Laos (1970-1972), the Indira Gandhi National Centre for the Arts (1988 to 1990), the Epigraphy Department of the Indian Institute of Archaeology, the Department of Ancient Indian and Asian Studies, Magadh University (vice-chancelor 1992-2010).
A scientific advisor to the Government of Cambodia, Dr. Sahai published several books on Angkor Thom, the Bayon, Preah Vihear. He is also the author of a five-volume work on the Lao Ramayana (Gvay Dorhabi), the Hindu temples of Southeast Asia, The Mekong River: Space and Social Theory, Pablo Neruda and India, India seen by the Siamese. Since 1976, he is the founder-editor of the South East Asian Review, founded with his late wife, Dr. Sudha Verma.