This study examined cross-cultural differences between Russian and British children’s physical self-perceptions and physical activity levels. The relationship between physical self-perceptions and physical activity behavior was also investigated. Two hundred and fifty-two Russian children (118 boys, 134 girls) and 240 British children (113 boys, 127 girls) aged 13 to 14 years completed Whitehead and Corbin’s (32) Physical Self-Perception Profile for Children (PSPP-C) and the leisure time exercise questionnaire (11). Results showed that boys from both nationalities were significantly more active than their female counterparts, and Russian boys participated in more moderate intensity activity than British girls. Multisample confirmatory factor analyses revealed that Russian and British children appraised the PSPP-C subdomains in similar ways, but the fit of the data to the hypothesized model was unsatisfactory. Russian children exhibited gender differences on all of the PSPP-C subdomains, but there was only one gender difference for the body-attractiveness subdomain in British children.