This study focused on measuring farm level technical efficiency among smallholder Irish potato farmers in Molo Sub County and its determinants. Descriptive research design was applied. Cross-sectional data was collected through multistage sampling from smallholder Irish potato farmers located in Molo Sub County from April to June 2019. A Stochastic frontier approach assuming a Cobb-Douglas production function was adopted to analyze the level of technical efficiency and explain variations in this technical efficiency across farmers and estimation was done by applying the maximum likelihood method. Mean technical efficiency was 70.7%. The statistically significant variables with respect to the farm inputs were land (0.262), seed (0.629), fertilizer (-0.299) and fungicide (0.131) variables respectively. However, fertilizer variable had negative effects on Irish potato production. Education (-0.061), gender (-0.262), access to extension services (-0.078) and farmer group (-0.217) variables were significant and influenced technical inefficiency negatively.Increase in smallholder farmers’ literacy level, accessibility to extension services and farmer groups may improve Irish potato production technical efficiency. However, gender contribution towards Irish potato production technical efficiency needs a deeper understanding.