This study aims to estimate technical efficiency of Thai commercial banks using output distance function. We adopted fixed effect model, random effect model, and maximum likelihood estimation to extract the technical efficiency with time-invariant and time-variant. With time-invariant, we found that technical efficiencies obtained by fixed and random effects are consistent. However, those are not consistent with technical efficiencies obtained by maximum likelihood estimation. With time-variant, the technical efficiencies of those banks obtained by fixed and random effects are consistent; while those are not consistent with technical efficiencies obtained by maximum likelihood estimation. However, average technical efficiency of each year from fixed effect, random effect, and maximum likelihood estimation are not quit consistent. We found that the financial liberalization between 1987 and 1997, the economic and financial reforms by IMF among the Asian financial crisis, and growth of GDP improve technical efficiency of Thai commercial banks.