Documented gender differences in physical activity rates during adolescence (Grunbaum et al., 2004) pose the question of whether physical activity enjoyment similarly differs between boys and girls. However, a necessary precursor to research on this topic is that the factor structure of the PACES be equivalent across gender. Although gender invariance of the PACES has been shown for children (ages 8-12 years; Paxton et al., 2008), there were no boys in the study on younger adolescents by Motl and colleagues (2001). Therefore, an understanding of whether the PACES scale is comparable between adolescent boys and girls is necessary. To address these questions, the authors examined the factorial validity and gender invariance of the PACES instrument in a sample of older adolescent boys and girls (ages 15-18 years). The first goal of the research was to determine whether the direction of the item wording presents a methodological artifact for this age group, as it does for younger populations. Second, the authors sought to determine whether factor structure, item loadings, and correlations between item errors were similar between boys and girls. (Contains 3 tables.)