Gunungkidul district, situated in the Karst Mountain area, represents one of the more poverty-stricken regions in Indonesia. The arid nature of this area, coupled with the scarcity of surface water, poses significant challenges to economic development endeavors, particularly in agriculture and animal husbandry. The vulnerability of the natural environment, unfavorable agro-climatic conditions, and unsuitable geographical features further hamper agricultural economic activities in the Karst Mountains of Gunungkidul. This condition causes dryland farm households to be vulnerable to food insecurity. Therefore, this study attempts to investigate dryland farm households’ food security in the Karst Mountain area and examine the associations of food insecurity using the share of household expenditure on food (SEF), energy intake levels, protein intake levels, and food security classification. Food security classification is specifically considered by two indicators, food expenditure proportion, and energy intake levels. The result showed that the number of family laborers, farming experience, household income, farm size, and production negatively impact the share of household expenditure on food. The average household energy consumption is sufficient, but the average protein consumption is less than others. Household food security in the Girisubo sub-district is still low since most households (70.09%) are undernourished, food vulnerable, and food insecure. Dryland farmer households need to get assistance from the local government or the private sector to grasp information about good expenditure management and food nutrition fulfillment in order to improve food security.