Actively open-minded thinking (AOT) is a crucial aspect in the education of adolescents; however, it has been insufficiently researched in the Spanish context. The purpose of this study is to analyse AOT and its relationship to critical thinking skills and personality. The participants in this research comprise 877 Spanish secondary school students. The study design is multidisciplinary, correlational and predictive. The findings show that personality traits, especially honesty, empathy and solidarity, and critical thinking skills, the development of new knowledge, analytical skills, and not learning by memory, are directly related to AOT. Actively open-minded thinking is the synapse of critical thinking because it allows for the achievement of objectives, reflection on and/or consideration of alternatives before making decisions. It is concluded that AOT is significantly related to the projection and value of critical thinking skills. Personality traits as well as identified competences can be used to integrate specific skills of both kinds of thinking into the educational curriculum.