Abstract Objective This study aimed to culturally adapt and validate the Spanish version of the SCS-Y. Method A sample of 664 Spanish adolescents (M = 13.34, SD = 1.61) from educational centers participated in the study. The sample was divided into independent subsamples for cross-validation. Construct validity was assessed using Confirmatory Factor Analysis (CFA), and measurement invariance was tested through multi-group CFA. Convergent validity was evaluated by correlating the SCS-Y with measures of depressive symptoms (RCADS), life satisfaction (SWLS), body esteem (BESAA), and eating disorder risk (EAT-26). Results CFA supported the original six-factor structure (Self-Kindness, Self-Judgment, Common Humanity, Isolation, Mindfulness, and Over-identification), demonstrating an acceptable fit after specifying a theoretically justified residual covariance. Full measurement invariance across gender was established. The total scale showed satisfactory internal consistency (⍺ = .79). Convergent validity was supported by significant correlations in the expected directions: self-compassion was positively associated with life satisfaction (r = .36) and body esteem (r = .45), and negatively associated with depressive symptoms (r = − .50) and eating pathology (r = − .31). Negative components (isolation and over-identification) showed the strongest links to maladaptive outcomes. Conclusion The Spanish version of the SCS-Y is a reliable and valid instrument for assessing self-compassion in adolescents. These findings underscore the importance of self-relating processes in adolescent mental health and support the use of this scale in clinical and educational research.