Several studies have pointed to the relationship between the affective and cognitive domains in science. The objective of this work has been to compare emotions, attitudes and levels of self-efficacy in STEM (Science, Technology, Engineering and Mathematics) areas in different educational stages. The research design was exploratory and quantitative. The sample consisted of 1097 students (540 from Secondary, 444 from Primary and 113 teachers-in-training). The measuring instruments investigated emotional and attitudinal factors based on the variables of the study. The results have revealed that positive emotions predominate in relation to STEM areas in Primary School, with an emotional decline as the academic level increases. In addition, positive emotions have predominated in experimental activities, and negative emotions in traditional activities. Primary and Secondary students considered that practical didactic strategies facilitate their learning. However, teachers-intraining have shown a preference for the use of traditional strategies during their teaching practices, considering that their students would learn with them. The levels of self-efficacy of the participants have varied depending on the academic level, and statistically significant differences have been found between the Secondary stage and the teacher in training, as in the latter the levels of self-efficacy in STEM areas decline.Diversos estudios han señalado la relación del dominio afectivo y el cognitivo en ciencias. El objetivo ha sido comparar las emociones, actitudes y niveles de autoeficacia ante áreas STEM (Science, technology, Engineering and Mathematics) en diferentes etapas educativas. El diseño de investigación ha sido exploratorio y cuantitativo. La muestra ha estado formada por 1097 estudiantes, 540 de Secundaria, 444 de Primaria y 113 maestros en formación. Los instrumentos de medida han indagado en factores emocionales y actitudinales en base a las variables del estudio. Los resultados han revelado que predominan las emociones positivas ante áreas STEM en primaria, existiendo un declive emocional al aumentar el nivel académico. Asimismo, han predominado las emociones positivas en actividades experimentales, y las emociones negativas en actividades de carácter tradicional. Los alumnos de primaria y secundaria han considerado que las estrategias didácticas prácticas facilitan su aprendizaje. Sin embargo, los maestros en formación han mostrado preferencia por el uso de estrategias tradicionales durante sus prácticas docentes, considerando que su alumnado aprendería con ellas. Los niveles de autoeficacia de los participantes han variado en función del nivel académico, y se han encontrado diferencias estadísticamente significativas entre la etapa de secundaria frente al maestro en formación, pues en este colectivo decaen los niveles de autoeficacia ante áreas STEM.