At IED Escuela Normal Superior Santa Teresita of the municipality of Quetame Cundinamarca, the need to implement a project that focuses on the development of critical thinking skills was identified, for which a research work is proposed that is implemented with a total of 30 ninth grade participants. The objective is to analyze the critical thinking achieved by the students from the theory of Dr. Richard Paul and Dr. Linda Elder, for this, it is described the state of development of critical thinking skills in relation to the environmental competencies, proposed in a learning project with an educational approach STEM, which is mediated by an EVA, whose validation is carried out from the ADDIE instructional model. The methodology used for the development of this research assumes a descriptive qualitative approach, which is carried out through participatory action research. Qualitative cut instruments are designed, for data collection that allow structuring the analysis from three intentions such as: the instruments referring to the design and validation of the EVA; those referring to the development of STEM environmental competencies pretest and postest and Those referring to the development of pretest and postest critical thinking. The main findings of this research show that effectively thinking critically implies having mastery of universal intellectual standards (Paul and Elder, 2003), that STEM education really enhances cooperative learning in different areas in an interdisciplinary framework, and that students developed competencies for the 21st century, in this case critical thinking on environmental problems.