Learning loss is expected for millions of children who have been out of school as a result of the current COVID-19 pandemic. Unfortunately, it is uncertain how much learning will be lost and how wide the gaps may be for disadvantaged children. This paper uses a unique longitudinal dataset to estimate learning loss during a three-month transition from Complementary Basic Education to government schools in Ghana. Our results show an average learning loss of 66 % of previous learning gains in foundational numeracy during this transition period. More importantly, we estimate widening gaps in learning loss according to lack of home learning support, as well as lack of home learning resources. Our results have implications for the provision of learning activities and support at home, not just during current school closures due to COVID-19, but also during transitions between academic years.