The purpose of this qualitative study rooted in the theory of planned behaviour (TpB) was to investigate South Korean physical education (PE) teachers' and female secondary school students' beliefs about girls' physical activity (PA) participation. Particular focus was given to the curricular and pedagogical factors influencing their engagement. Participants of this study were six PE teachers and 12 female students (two from each teacher's PE programme, one identified as having low PA and the other high PA) in two public middle schools and four public high schools in South Korea. Data were collected through demographic questionnaires, a series of semi-structured interviews with each PE teacher and one with each female secondary school student, and non-participant observations (e.g. fieldnotes) of three lessons of each PE teacher. The data were analyzed through thematic analysis using TpB to guide the coding (e.g. attitude toward the behaviour, subjective norms, and perceived behavioural control). Findings indicated that the teachers assumed mixed-gender and traditional curriculum were core barriers, whereas the female students had more diverse and conflicting perspectives, but overall, expressed desire for more choice within the curriculum. Teacher and student beliefs are compared, and pertinent pedagogical implications are provided in light of their differences.