The Suicide Cognitions Scale (SCS) has demonstrated considerable promise as a risk screening tool, although it has yet to be validated for use with adolescents or in Spanish-speaking populations. The aim of this study was to develop a Spanish version of the 16-item SCS-Revised (SCS-R) and to examine its psychometric properties in a sample of adolescents. Participants were 172 adolescents aged between 12 and 18 years (M = 15.32, SD = 1.57) and currently in residential care. They completed the Spanish SCS-R and a series of other psychological measures. The psychometric properties of the SCS-R were examined through factor analyses and testing of convergent/discriminant validity and construct validity. Factor analyses supported a bifactor structure, indicating that SCS-R items were primarily measuring a common underlying latent variable. SCS-R scores were positively correlated with multiple indicators of psychopathology and other suicide risk factors (e.g., depression, hopelessness) but negatively correlated with protective factors (e.g., believing that one’s mental pain will eventually end). Importantly, SCS-R scores differentiated adolescents in residential care who had previously attempted suicide from those who had only thought about suicide. Scores also differentiated adolescents who had previously attempted suicide from those who had previously only engaged in non-suicidal self-injury. This constitutes further evidence that the SCS-R measures a construct that distinguishes suicidal thought from action and is specific to suicidal forms of self-harm. Overall, the results suggest that the Spanish SCS-R is a potentially useful tool for identifying adolescents at risk of attempting suicide in residential care.