This study has two main goals: (a) to compare whether objective and self-reported PA levels, and motivational regulations were similar among European adolescents with different cultural norms, and (b), to analyse whether the associations between those motivational regulations towards objective and self-reported PA levels vary across Spanish and French cultures. Data were collected from 637 adolescents (50.9% Spanish, 40.8% girls). Participants completed questionnaires on motivational variables and subjective PA. Objective PA was assessed by accelerometer. Data were analysed by structural equation modelling and invariance tests. Cross-country differences were found in objective PA levels and motivational factors, with Spanish obtaining higher values than French adolescents. Association of motivational factors with PA was similar regardless of the cultural origin of subjects. This study reinforces the premises of SDT according to cross-country validity. Intervention strategies should focus on encouraging the most self-determined motivational forms regardless of the culture of origin.