The main purpose of this study is to examine the average and farm-specific technical and economic efficiencies of the farms producing lentil at Faridpur district of Bangaldesh and to identify the factors causing inefficiency. Stochastic frontier analysis is used to measure technical and economic efficiencies. Eighty seven randomly selected farmers have been interviewed for collecting data on farm-specific characteristics, output, input prices and costs during the production period July 2010 to June 2011. Results reveal that the mean technical and economic efficiencies are 67.94% and 72.32% respectively. Farmers might increase lentil production on an average by 32.06% without increasing present levels of inputs. In other words, at full technical and economic efficiency levels, on an average, farmers could reduce their inputs by about 47% and their expenditure on inputs by about 38% without reducing their present levels of lentil production. In the inefficiency effect models, the estimated parameters show that higher level of farmers’ age and education and higher training facility result in higher technical efficiency. Besides higher access to micro-credit results in higher technical and economic efficiencies while higher access to extension services exhibits lower values of both the efficiencies. This study lights on the strategies such as organizing training programmes by extension department, encouraging more educated and aged people in lentil farming to increase technical efficiency and expanding micro-credit provision to increase both the technical and economic efficiencies.