This study quantified technical efficiency and the determinants of observed technical inefficiency of sawmills in Nigeria. A two-stage sampling technique was used to select 170 sawmillers in Ondo and Osun states, while questionnaire was used to obtain data from them between October and December 2003. The stochastic frontier approach was used to estimate technical efficiency of both small- and medium-scale sawmills, while the ordinary least square (OLS) regression analysis was used to estimate the determinants of the observed technical inefficiency. Empirical results indicate that medium-scale sawmillers are more efficient than their small-scale counterparts. However, both groups of sawmillers in Nigeria have potentials to expand their output.