This study investigated the psychometric properties of a Turkish-language adaptation of the Social and Emotional Health Survey-Secondary (SEHS-S), a measure of core psychological assets hypothesized to be associated with adolescents' flourishing mental health. Convenience samples of students (Grades 9-12) from six Turkish high schools were used; one sample had 402 students (45% male and 55% female) and the second sample had 452 students (44% male and 56% female). Using Sample 1, confirmatory factor analysis replicated the previously identified SEHS-S higher-order factor structure, consisting of 12 subscales that formed four first-order latent traits (belief-in-self, belief-in-others, emotional competence, and engaged living) and a second-order trait (covitality). Using Sample 2, additional validity analyses showed that covitality was positively correlated with psychological resilience and prosocial behaviors. There was a negative correlation with externalized and internalized psychological distress. Acceptable alpha reliability coefficients were found for the four SEHS-S domains (males = 0.74-0.89; females = 0.75-0.81) and the covitality total score (0.89 for males and females). The findings supported the use of the SEHS-S as a valid and reliable measurement instrument for use in positive mental health research with Turkish adolescents and generalized the SEHS-S covitality measurement model to another cultural context.