The research on "Self-management of Hill Tribe Farmers under the Sufficiency Economy Philosophy in the Royal Project" was conducted to study the hill tribe farmers under the Sufficiency Economy Philosophy in the Royal Project area on the following aspects: 1) self-management of hill tribe farmers, 2) problems and obstacles in self-management of hill tribe farmers, and 3) self-management model of hill tribe farmers. This study was both quantitative and qualitative research. The study showed that hill tribe farmers practiced self-management under the philosophy of sufficiency economy on a regular basis. On the relationship between respondents’ demographic characteristics and economic and social factors of hill tribe farmers in the Royal Project area using multiple regression analysis, the values were F = 3.301; Sig = 0.000. These values meant that there was at least 1 independent variable that is related to the dependent variable in a linear form. When considering the multiple coefficient of determination (R2), R2 is equal to 0.111, which meant that all independent variables can explain the variation (change) of the variables under self-management practices under the philosophy of sufficiency economy of the hill tribe farmers in the highland areas of the Royal Project as 11.1 percent. Of the 13 independent variables, there were 2 independent variables affecting the variables with statistical significance at the level of 0.05, namely, land ownership status and debts.
Concerning problems and obstacles on self-management of tribal farmers under the philosophy of sufficiency economy in the Royal Project area, the study found that on the capital investment, farmers had spent more, where funding was not enough. On debts the farmers had to borrow money for buying necessary items. Life values and lifestyle had changed due to the acquired practice of purchasing from convenience stores. Regarding carrying on the occupation, the farmers had to encounter with the market problems such as dealing with the middlemen and the unreliable prices of agricultural produce. Lastly, on daily expenses, the farmers had to tackle increasing prices of goods.