Tree species inventories, particularly of poorly known dry deciduous forests, are needed to protect and restore forests in degraded landscapes. A study of forest stand structure, and species diversity and density of trees with girth at breast height (GBH) ≥10 cm was conducted in four management zones of Bannerghatta National Park (BNP) in the Eastern Ghats of Southern India. We identified 128 tree species belonging to 45 families in 7.9 hectares. However, 44 species were represented by ≤ 2 individuals. Mean diversity values per site for the dry forest of BNP were: tree composition (23.8 ±7.6), plant density (100.69 ± 40.02), species diversity (2.56 ± 0.44) and species richness (10.48 ± 4.05). Tree diversity was not significantly different (P>0.05) across the four management zones in the park. However, the number of tree species identified significantly (P<0.05) increased with increasing number of sampling sites, but majority of the species were captured. Similarly, there were significant variations (p<0.05) between tree diameter class distributions. Juveniles accounted for 87% of the tree population. The structure of the forest was not homogeneous, with sections ranging from poorly structured to highly stratified configurations. The study suggests that there was moderate tree diversity in the tropical dry thorn forest of Bannerghatta National Park, but the forest was relatively young.