Universal Primary Education is one of the main objectives of development aid. However, very little empirical evidence of its effectiveness actually exists. Until recently, the quality of the available data has not been good enough to obtain robust results about the relationship between international aid and educational achievement. In this paper the most recent disaggregated reliable data available is used to study the relationship between aid for education and educational achievement. The focus here is on the educational variables for coverage, gender equality, and process. The cultural proximity between donors and recipient countries is used as an instrument to tackle endogeneity. Our results are very robust and indicate that aid for primary education has a strong positive effect on primary school enrolment, and gender equality. A reduction in repetition rate is also found, but no effect on the pupil/teacher ratio nor the percentage of trained teachers is observed.