Both Jasmine and non-Jasmine rice yields in Thailand are substantially lower than their respective average world rice yields. Sources of yield variations in both kinds of rice, i.e., production inputs, technical inefficiency and other factors, are investigated in this study. Factors affecting technical inefficiency of production are analyzed simultaneously with the estimation of the production frontiers using the method of maximum likelihood. Cobb-Douglas stochastic yield frontiers are used to investigate policy implications. The crucial factors influencing Jasmine rice yields are technical inefficiency, chemical fertilizer, labor, transplanting, irrigation, severe drought and neck blast, whereas for non-Jasmine rice, the same factors are significant, except for labor, neck blast, and transplanting, but other chemicals had a significantly positive effect. Factors negatively affecting technical inefficiency for non-Jasmine rice are the ratio of male labor to total labor and experience reflected by the age of the farmers, while labor influences in the positive direction. For Jasmine rice, only the male-labor ratio significantly influences technical inefficiency.