Maize is a staple food and its adequacy is a measure of food security in Busia County and across Kenya. Despite myriad efforts to increase its yield, the national level has remained low at 1.6 tons/ha relative to world average of 5.5 tons/ha and Busia County experiences much lower yield of 1.2 tons/ha. This low yield in the county coupled by high population growth rate arising from a fertility rate of 6 percent in the county when national level is 4.6 percent and a large population of women within productive age puts the county’s food security at stake. The County’s proximity to Uganda also contributes to inflow of cheap maize from Uganda making the crop less viable for agribusiness within this County. In attempts to support maize farming, One Acre Fund, a nongovernmental organization has intervened through provision of farm inputs such as fertilizer and seeds as well as extension services among others. Thus this study sought to investigate the impact of interventions by One Acre Fund on maize yield and profit from maize farming in Busia County in Kenya. The study used primary data collected from a sample of 264 maize farmers’ family heads using questionnaires with both closed and open ended questions. The county was first stratified into constituent sub-counties out of which two sub-counties of Nambale and Teso North were randomly selected. The study sample was then drawn randomly from these two sub-counties. Robust regression result showed that improved inputs (using certified seeds and organic fertilizers as proxies) had the effect of increasing maize yield. In addition regression adjustment results showed that maize yield increases with increase in level of education of farm family head. More so, profit was noted to rise as more inorganic fertilizer is used in planting as well as with increase in manure usage. Nevertheless the increase in the application of chemical fertilizer (inorganic fertilizer) was estimated to lower profits. Propensity score matching estimation results using three matching algorithms interchangeably which are: nearest neighbor, kernel matching and radius matching with a radius of 0.01 indicated that One Acre Fund farmers managed to achieve significantly higher yields than similar non-members. The effect of One Acre Fund on profit was positive but insignificant. The study recommends expansion of One Acre Fund membership and increased use of organic and inorganic fertilizer.