Forests have played a vital role in the socio-economic development of Nepal with their productive, protective, and bio-esthetic functions. Stand height-diameter as well as volume estimation is very critical in forest management. This research modelled height-diameter relationship as well as tree volume for Teak (Tectona grandis), a well-known tropical hardwood species, in central lowland Nepal. Data was collected from a Teak plantation site in Sagarnath Forest Development Project (SFDP), Nepal. Forty-four trees representing different diameter classes were felled. The diameter at breast height (dbh) and height (H) of the trees ranged from 6.1 to 58.9 cm and 6.1 to 26.1 m, respectively. Several height-diameter models were fitted and evaluated for certain training and validating criteria. The height-diameter equation of 12H=[- 5.2544 + 6.8603×lndbh]"> , performed well and was selected to be the best model for H prediction from dbh. Also, the volume equation of 12V=[0.3364+0.0685×dbh+-0.097×H] "> was selected as best fitted equation, using dbh and height as independent variables. The height in this volume equation was to be calculated from selected height-diameter equation to predict height. The equations developed are the first of their kinds officially documented for Teak species in central lowlands of Nepal.