<p align="justify">The purpose of the study was to analyze the relations between perception of a motivational climate, motivational mediators, self-determined motivation and discipline, as well as the motivational variables that predicted discipline and indiscipline. For it, Learning and Performance Orientations in Physical Education Classes Questionnaire (LAPOPECQ), Educative Motivation Scale (EME), Basic Psychological Needs Scale (BPNES) and Disciplined and Undisciplined behaviours in Physical Education Classes Inventory (ICDIEF) were given to 155 students of the second cycle of E.S.O and 1st course of Baccalaureate. The results showed that discipline related positively and significantly with perception of a task climate, intrinsic and extrinsic motivation and negatively and significantly with amotivation. On the other hand, discipline was predicted positively by task climate, and indiscipline positively by amotivation, ego climate and competence mediator, and negatively by autonomy mediator. Therefore it should be principally fomented a task-involving climate in physical education classes, avoiding that students fell in amotivation, favoring the basic psychological needs&rsquo; satisfaction and, as a result, the most self-determined motivational shapes.<br /><strong>Key Words:</strong> achievement goals, self-determination, psychological mediators, discipline, young students</p><p align="justify">El objetivo del estudio fue analizar las relaciones entre la percepci&oacute;n del clima motivacional,&nbsp; los mediadores psicol&oacute;gicos, la motivaci&oacute;n autodeterminada y la disciplina, as&iacute; como qu&eacute; variables motivacionales predec&iacute;an la disciplina e indisciplina. Para ello, se pasaron el Cuestionario de orientaci&oacute;n al aprendizaje y al rendimiento en las clases de educaci&oacute;n f&iacute;sica (LAPOPECQ), la Escala de Motivaci&oacute;n Educativa (EME), la Escala de medici&oacute;n de las Necesidades Psicol&oacute;gicas B&aacute;sicas (BPNES) y el Inventario de conductas de Disciplina-Indisciplina en educaci&oacute;n f&iacute;sica (ICDIEF) a 155 estudiantes de segundo ciclo de la E.S.O y 1&ordm; de Bachillerato. Los resultados mostraron que la disciplina se relacionaba positiva y significativamente con el clima tarea, la motivaci&oacute;n intr&iacute;nseca y extr&iacute;nseca, y negativa y significativamente con la desmotivaci&oacute;n. Por otro lado, la disciplina fue predicha positivamente por el clima tarea, y la indisciplina positivamente por la desmotivaci&oacute;n, el clima ego y el mediador competencia, y negativamente por el mediador autonom&iacute;a. Por consiguiente, se deber&iacute;a fomentar fundamentalmente un clima motivacional que implique a la&nbsp; tarea en las clases de educaci&oacute;n f&iacute;sica, evitando que los estudiantes cayeran en la desmotivaci&oacute;n, favoreciendo la satisfacci&oacute;n de las necesidades psicol&oacute;gicas b&aacute;sicas y, consecuentemente, las formas de motivaci&oacute;n m&aacute;s autodeterminadas. <br /><strong>Palabras Clave:</strong> metas de logro, autodeterminaci&oacute;n, mediadores psicol&oacute;gicos, disciplina, j&oacute;venes estudiantes</p>