Educational access in developing countries has improved significantly in recent years, but less evidence is available on learning and learning progress in comparative perspective. This paper employs data from Young Lives to examine levels and trends in cognitive skill development and the links to enrolment in school across the four study countries for pupils aged five to 15. Non-continuous patterns of enrolment are linked to lower learning levels in all countries, as are key indicators of home background disadvantage. Large differences in learning and learning progress are also found between the four countries' education sytems, with "learning gains" being typically highest in Vietnam and much lower in India (Andhra Pradesh) and Ethiopia. Inequalities linked to prior learning and home backgrounds are wide in Peru, while in Ethiopia and India relatively low levels of learning progress are a more general concern. In Ethiopia, both enrolment and quality improvements remain priorities for policy, while in India high levels of primary school enrolment, at younger ages than in the other study countries, suggest that comprehensive quality improvements may be required, nonetheless with a focus on disadvantaged pupils and those with low attainment in the early years.