Policies fronting commercialization of agriculture in Kenya assumed that realization of increased household incomes, through cultivation of cash crops, would guarantee improved food security and subsequent reduction of poverty. Population pressure has led to competition for limited land resource, coupled with unfavorable poverty indicators; they have impacted negatively on food access in the district. Factors influencing households’ food security among smallholder tea farmers in Nandi South was investigated using a modified Almost Ideal Demand System (AIDS). Multi-stage proportional-to-size cluster sampling was used to sample 180 households. Results showed that income, savings, food storage, land productivity, off-farm income, ratio of land allocated to tea significantly influence household dietary diversity. Policies that aim at improving household food security among smallholder cash crop farmers should target at increasing and diversifying household income sources and farm enterprises, provision of saving opportunities, storage facilities and proper allocation of land resource between cash crops and food crops.