Abstract:  This paper reports results from a three-year field experiment conducted in high schools in rural Tanzania. Three treatments tested (1) incentives, (2) technology and (3) both of the above. Incentives provided cash to students for scores on year-end mathematics tests. Technology provided solar-energy access, bilingual textbooks and videos. Results show significant evidence of complementarity between incentives and technology, and no effect of either alone. Thus low student motivation, not just deficient technology, constrained achievement. I estimate a pre-specified structural model to understand students' valuation of achievement given different treatment conditions, and explore heterogeneity.