The Ethiopian education system has been very dynamic over recent years, with a series of large-scale education program interventions, such as the Second Phase of General Education Quality Improvement Project (GEQIP-II) that aimed to improve student learning outcomes. Despite the large-scale programs, empirical studies assessing how such interventions have worked and who benefited from the reforms are limited. This study aims to understand the impact of the reform on Grade 4 students’ maths learning outcomes over a school year using two comparable Grade 4 cohort students from 33 common schools in the Young Lives (YL, 2012-13) and RISE (2018-19) surveys. We employ matching techniques to estimate the effects of the reform by accounting for baseline observable characteristics of the two cohorts matched within the same schools. Results show that the RISE cohort started the school year with a lower average test score than the YL cohort. At the start of Grade 4, the Average Treatment Effect on the Treated (ATT) is lower by 0.36 SD (p<0.01). In terms of learning gain over the school year, however, the RISE cohort has shown a modestly higher value-added than the YL cohort, with ATT of 0.074 SD (p<0.05). The learning gain particularly is higher for students in rural schools (0.125 SD & p<0.05), which is also stronger among rural boys (0.184 SD & p<0.05) than among rural girls. We consider the implications of our results from a system dynamic perspective; in that the GEQIP-II reform induced unprecedented access to primary education, where the national Net Enrolment Rate (NER) rose from 85.7 percent in 2012-13 to 95.3 percent in 2019-20, which is equivalent to nearly 3 million additional learners to the primary education at a national level. This shows that learning levels have not increased in tandem with enrolment, and the unprecedented access for nearly all children might create pressure on the school system. Current policy efforts should therefore focus on sustaining learning gains for all children while creating better access.