Quality early childhood education (ECE) can improve children's learning and development in low- and middle-income countries, but little evidence exists of programs targeting marginalized girls in vulnerable rural communities. This study used a matched-pair mixed-methods community-randomized trial to evaluate a preschool program for marginalized girls (N = 466, M[subscript age] = 5-years; W[subscript 1] = 2022; W[subscript 2] = 2023) from 16 rural Hausa-ethnic communities in Nigeria. The program yielded considerably large impacts on every domain of school readiness assessed (dt = 0.89-1.52). In qualitative interviews (N = 30, data collected in 2023), parents discussed witnessing their daughters' learning and development as well as their future educational and life goals for their daughters. Results demonstrate that access to high-quality ECE in highly disadvantaged communities can dramatically improve girls' learning and potentially change parental perceptions about girl-child education.