Do well-informed politicians make more effective public spending decisions? In experiments with almost all (N=460) elected politicians in Malawi, we tested the effects of information on public spending by providing information about school needs, foreign aid and voting prior to real spending decisions. We show that this intervention reduced inequalities in public spending: treatment group politicians were 30% more likely to spend in schools neglected by donors, and 18% more likely to spend in schools at the highest quartile of need. Treatment effects were often greatest in remote and less populated communities. The effect of some treatments also increased when politicians were told that they were being observed by voters or donors, suggesting that greater transparency increases demand for accurate information. These results provide a novel explanation for inequalities in spending and imply social welfare benefits from improving politicians’ access to and demand for information about community needs.