Although growing attention has been paid to motivation in explaining active travel to school among young people at the international level, no measures of motivation for active commuting to school (ACS) were found in Sweden. Guided by self-determination theory, this research aimed to adapt the Behavioral Regulation in Active Commuting to and from School (BR-ACS) questionnaire to the Swedish context and test the resulting version’s psychometric properties. The purposive and cross-sectional sample included 273 students (58 % girls, aged 10–12 years) from four Swedish urban schools. Results from confirmatory factor analyses psychometrically supported the six-factor correlated model (intrinsic motivation, integrated regulation, identified regulation, introjected regulation, external regulation, and amotivation) and the hierarchical three-factor model (autonomous, controlled motivation, and amotivation), which were invariant across gender. Latent correlations underpinned a symplex-like pattern. Discriminant and convergent validity and reliability were gathered. Criterion validity evidence was met with positive associations from intrinsic motivation, integrated and identified regulation to ACS, and a negative relationship between amotivation and ACS. The Swedish version of the BR-ACS questionnaire is a valid and reliable measure of children’s motivation toward ACS.