By the time children in low- and middle-income countries start primary school, large socioeconomic disparities are evident in children's learning and development. Both pre-primary and home environments can play important roles in influencing school readiness and can contribute to disparities in early childhood development, but there is limited evidence on their relative roles in low- and middle-income countries. This paper examines how pre-primary quality, stimulation at home, and early childhood development vary by socioeconomic status for pre-primary students in the Arab Republic of Egypt. The results demonstrate substantial socioeconomic inequality in stimulation at home, more so than in pre-primary quality and inputs, although there is variation in the degree of inequality across different dimensions of pre-primary quality. "Double inequality" is observed, where students with less stimulating home environments experience slightly lower quality pre-primary inputs. There are particularly large pre-primary inequities in structural quality (physical environment) and less inequity in process quality (pedagogy). These results suggest that targeted investments in pre-primary education in Egypt are necessary to reduce inequality in school readiness but are likely insufficient to close the socioeconomic status gap in children's development. Investing in interventions to improve vulnerable children's home learning environments, as well as investing in quality pre-primary, is critical to address disparities in children's development. [This paper is a product of the World Bank's Education Global Practice. The study is the result of a collaboration between the World Bank and the Ministry of Education and Technical Education of Egypt (MOETE). It was funded by the UK Strategic Partnership for Egypt's Inclusive Growth Trust Fund and the World Bank.]