Terminalia tomentosa (Roxb.) Wight & Arn., an important tree species in the tropical forests of India, is often reported to have poor or no regeneration in many parts of the country. The present study was conducted to evaluate the population structure and regeneration status of the species in three different forest types of the Similipal Biosphere Reserve, along with phenological behaviours for two consecutive years. Leaf initiation was positively correlated with fruit senescence (r = 0.76, p < 0.01) and flower initiation (r = 0.63, p < 0.01). However, a negative correlation was found between leaf initiation (LF2) and leaf senescence (LF5) (r = –0.42, p < 0.05). Principal Component Analysis showed that maximum temperature and rainfall in a given month are the main factors for pre-monsoon events (leaf senescence and fruit senescence) and post-monsoon events (growth and maturation of leaves and fruits). The results also revealed that regeneration failure of T. tomentosa was not due to phenological intensity but possibly to wrong phenological timing of fruit maturation. This study on regeneration status and phenological information of T. tomentosa could help develop strategies for conservation and management of this tropical tree species in its natural ecosystem.