This study on Acceleration and Gifted Girls investigates acceleration as an intervention in secondary education within girls’ schools in New Zealand. It explains the extent that acceleration is being used for whom and with what processes in the context of New Zealand single-sex education. It focuses particularly on acceleration. A national survey of single-sex girls’ schools provided a general view of acceleration practices and provisions. Three case studies offered a more in-depth exploration. Findings from this study emphasised that schools are designing and evaluating their provisions for their gifted and talented girls, with an emphasis on personalised learning and an appropriate curriculum. Acceleration is used, typically, as part of a continuum of provisions to challenge students at higher levels than their year level. Timetable flexibility, whole class and individual acceleration, multi-level pathways through NCEA, dual enrolment or full entry at universities are all included in the provisions offered to gifted girls. This study highlighted an association between a school’s culture of learning and the school’s culture of care of gifted and talented students. High levels of satisfaction relating to the ways in which schools provided for gifted and talented girls were expressed by both students and their parents.