The expansion of schooling in developing countries has improved educational access 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 fifteen.  Enrolment is high in all countries except Ethiopia, where it is improving relatively equitably over time, but pupils who do not enroll in school or whose enrolment is interrupted are strongly disadvantaged in terms of learning.  At younger ages, pupils in India master basic cognitive skills comparatively well, but by age 12 learning progress is closer to that in Ethiopia, while both learning and learning progress are notably higher in Peru and Vietnam.   Inequalities in learning progress are strongly linked to differences in home backgrounds in all countries, but while improving enrolment remains an issue in Ethiopia, generally low levels of learning progress in both Ethiopia and India suggest that more general education quality improvements are a key priority.  In Vietnam and Peru, high attainment by more advantaged pupils and those who perform well in the early years suggests that equity improvements intended to reduce "gaps" are key to more general improvements in learning achievement.   

 Keywords: Cognitive skills; learning profiles; longitudinal studies; educational access; poverty.

The final published version of the article is available on the journal website.