The study was conducted in Oak-dominated temperate forests of Rajouri district of Jammu and Kashmir (India) to assess the impact of altitude on species composition and diversity. A total of 32 woody species were encountered in the study area lying between 1200m and 2500m elevation. Three species of Oak viz. Quercus leuchotrichophora, Q. floribunda and Q. semecarpifolia were found to be dominant or co-dominant in the area. Q. leuchotrichophora shared the maximum acreage at all elevations. Its associate species, however, remained changing across the elevational gradient. Results revealed that the phytosociological characteristics of the studied forests vary remarkably in response to changes in altitude. Stem density decreased while as total basal area was found to increase with altitude. No of species was maximum at lowest altitude and steeply decreased with rise in altitude.  Diversity indices (Margelef Index, Menhinik Index, Shanon Wiener Index, etc.) showed evident decline in their values with altitude. However an unexpected dip due to anthropogenic pressure at middle elevational range was also observed. These forests demand urgent attention for their conservation and management.