Physical activity (PA) is linked to numerous health advantages, but adolescents typically demonstrate inadequate levels of PA with girls engaging in less PA than boys. This study aims to explore the factors hindering and promoting PA among girls aged 11-18 yrs, examining how existing literature addresses these factors through an ecological framework. A scoping review was conducted using the PRISMA-ScR protocol. Six databases were interrogated between October 2022 and November 2024, and 41 articles were analysed. The main barriers to PA for girls were their relationship with their bodies and the influences of peers and teachers, while the main facilitators were social interactions, family or teacher support and choice of activity. These findings highlight the importance of developing a socio-ecological framework that addresses personal, interpersonal, and environmental factors to enhance understanding of the issue of girls’ engagement in PA.