We use a randomized experiment (across 200 public primary schools in Puebla, Mexico) to study the impact of providing schools with cash grants on student test scores. Treated schools received on average ∼$$ \sim $$16 USD per student each year for two years, an increase of ∼$$ \sim $$20% in public spending per child, after teacher salaries. Overall, the grants had no impact on student test scores. Lack of a treatment effect does not seem to be driven by poor implementation or a substitution away from other inputs (e.g. household expenditure).