Self-consciousness development takes place mainly in adolescence because the brain undergoes certain structural changes that facilitate abstract thinking and metacognition, thus favoring the development of identity. Despite the importance of self-consciousness for mental health, there are no specific measurement instruments for Spanish adolescents. The objective of this study was to explore the dimensions of self-consciousness among Spanish adolescents aged between 13 and 18 years and validate the Chinese Adolescent Self-Consciousness Questionnaire (ASC) in this population. A second-order confirmatory factor analysis (CFA) was conducted in accordance with previous validations of the ASC, using R Studio and the Lavaan package, to test its adequacy in a Spanish sample. Internal consistency and temporal stability were also tested, and evidence of validity was found. The results showed a good fit to the model eliminating four items with poor fit indices, CFI = .90, TLI = .89, RMSEA = .078, 95% CI [.076, .080]. Higher self-consciousness was associated with greater self-esteem and lower depressive symptomatology. No significant gender differences were found. This study provides a valid measure to evaluate self-consciousness in Spanish adolescents. The relationship established between self-consciousness and anxiety and depression requires further study as self-consciousness is involved in the development and maintenance of adolescent psychopathology.