Increasing productivity is a challenge for small farmers in managing their farms. The objectives of this study were to analyze the technical efficiency of potato farming using local knowledge of traditional agriculture and to analyze the variables that contribute to the technical inefficiency of potato farming in the Arfak Mountains. This study was conducted in three districts of the Arfak Mountains Regency of West Papua Province: Anggi, Sururey, and Hingk. This study used cross-sectional data obtained from structured interviews with 140 farmers. The determinants and efficiency levels were estimated using stochastic frontier analysis. The findings of this study indicate that farmers who implement traditional farming systems with local knowledge have an average technical efficiency of 52%, equivalent to the average technical efficiency value of potatoes in other developing countries without local knowledge of 40–70 percent. The variables of extension frequency, total household income, degree of output commercialization, distance between the farmer’s house and the farm location, and fallow length are the determining factors for farmers' technical efficiency. The implication is that traditional farmers can improve their technical efficiency through technological improvements, the use of appropriate inputs, infrastructure improvements, intensive counseling, and assistance in correctly managing their farms.