Various studies on the formation of critical thinking in teachers express difficulties in the training of teachers at different levels of education. Some of them recognize conceptual dispersion evidenced in their conceptions and explanations; others recognize curricular gaps without clear and coherent programs for their development; and a third group recognize that training in critical thinking requires both academic training as well as personal training of the subject. Most of the studies agree on training teachers from all fields of knowledge, where theoretical and methodological elements are provided to form critical thinkers. For this reason, the present research, developed with five teachers from different areas of secondary education in which different sources of information were collected and analyzed, contributes to the reflection with different theoretical perspectives and methodological strategies used by teachers, which were contrasted with the theories of critical thinking (psychological, philosophical and didactics of sciences).