<p>Social identity plays a pivotal role in understanding group dynamics and performance in sport. Although the Social Identity Questionnaire for Sport (SIQS; Bruner &amp; Benson, 2018) provides a brief and multidimensional tool to assess athletes’ social identity strength, there is a need to evaluate its psychometric properties in different languages and cultural contexts. As such, this study examined the French version of the SIQS and its measurement and structural invariance across diverse athlete populations. Using a sample of 915 athletes, multi-group confirmatory factor analyses were conducted across sex, type of sports, and competitive levels. Results supported the original global and multidimensional structures of the instrument and demonstrated its measurement invariance, confirming its robustness across groups. Latent mean differences highlighted nuanced variations in social identity strength between male and female athletes as well as between individual- and team-sport participants. These findings establish the French SIQS as a valid and reliable instrument for assessing social identity in sport and provide a foundation for future cross-cultural and longitudinal investigations. This study underscores the instrument’s potential for advancing our understanding of social identity dynamics within diverse sporting environments.</p>