It has been well documented in the literature that parental cognitions contribute in central ways to child development and adjustment. Nevertheless, there are no other questionnaires in the Spanish context that measure parents’ perceptions toward their adolescent children’s efficacy. This study aims to develop and validate a new scale to measure parents’ perceptions toward their adolescent children’s efficacy. A total of 594 Spanish parents and their children aged between 11 and 16 years completed the General Self-Efficacy Scale (GSE), the Adolescent General Efficacy Scale for Parents (AGES-p), and the Adolescent Future Expectations Scale for Parents (AFES-p). Non-probability convenience sampling was used. We kept similar proportions in our sample when selecting participating schools (75.90% State schools and 24.10% private schools). The psychometric properties of the AGES-p scale were examined using Exploratory and Confirmatory Factor Analysis. We obtained a unidimensional factor structure, which explains 66.77% of the variance. This means that most of the observed variance in item responses is explained by a single latent construct. The reliability (α = 0.926) and convergent validity of the scale were found to be high. It can be observed that there are positive and significant correlations between AGES-p and the questionnaires used: GSE (r = 0.268) and AFES-p (r = 0.508).The AGES-p has the potential for evaluating parents’ perception toward their children’s efficacy. This scale in the Spanish context provides a new measurement instrument to the field of family evaluation, applicable both to research and psychoeducational, clinical, and social interventions.