This study on the feeding ecology of Himalayan Gray Langur or the Chamba Sacred Langur Semnopithecus ajax is a crucial baseline step as very little is known about this species due to its long taxonomic uncertainty and limited distribution range. This study was done in Kalatop-Khajjiar Wildlife Sanctuary, Chamba, Himachal Pradesh using scan sampling method. A total of 71 scan samples were collected in the study area from September 2020 to November 2020 focusing on the autumn diet of the species. Group size, group composition, and distribution of the langurs were also recorded. Totally, 20 species of plants belonging to 15 different botanical families were recorded which contribute to the diet. Hedera nepalensis, Quercus oblongata, and Ilex dipyrena formed the major components of the diet. The langurs consumed a substantial portion of leaves (84.32%), followed by fruits and flowers. Mature leaves being a part of the diet of langurs has proven the broaden repertoires of langurs inhabiting the Himalayan landscape. Also, a difference in the diet composition of two study groups was recorded which might be the result of varying distribution with respect to elevation.