[eng] This article investigates the effects of the socio-environmental theme in the development of critical thinking skills in the future primary school teachers, through the stse approach. A quasi-experimental pretest / postest design and two types of instruments, were used: a didactic intervention instru-ment, consisting of some teaching-learning sequences, and the second instrument, an adaptation of the Halpern test, was used to assess critical thinking skills for socio-environmental situations. The pretest showed a low level of critical thinking skills. After the intervention, the statistical analysis showed very favorable significant changes in two of the skills evaluated, the argument analysis and decision-making and problem solving. In addition, the intervention allowed students to make a critical reflection on the positive and negative aspects of science and technology, the relationships between them and with society and the environment