This article investigated the causal relationship between public agricultural research expenditures and agricultural output in Lesotho. Cointegration and Granger-causality tests were performed to determine the causal relationship between agricultural research and agricultural output. Lag length tests were performed to facilitate the Cointegration analysis. Results of the empirical analysis indicated that agriculture in Lesotho is driven by agricultural research. The results also showed that it takes seven to eight years for public agricultural research expenditures to have a significant impact on agricultural output in Lesotho.