This study investigated determinants of agricultural productivity in Uganda using quarterly data for the period 2007 to 2017. Descriptive statistical and econometric methodologies were utilized to analyze the data. The variables that were considered consisted of agricultural productivity, expenditure on capital (including on-farm irrigation and infrastructure), research and development investments in agricultural research, expenditure on extension services and population growth rate. According to the regression results, the determinants of agricultural productivity in Uganda at 5 percent level are; research and development investments in agricultural research, expenditure on extension services and population growth. The study recommends increased investment in Uganda’s agriculture research and development since these are key sources of agriculture productivity growth since this can change the production process by applying innovation, newly achieved scientific and practical knowledge and through management skills.