Grounded in achievement goal theory and self-determination theory, the aim of this study was to analyze the motivational determinants of precompetitive anxiety in the sports context, considering the horizontal motivational sequence: adaptive social factors, competence need, types of motivation, and consequences. This study was also conducted in order to analyze the mediating role of the need for competition and motivational regulations on social factors and consequences. The sample consisted of 217 athletes of both sexes engaged in elite sport, who answered (...) a series of questionnaires to measure study variables to develop an analysis of the structural equation model. The results showed that both the task-involving climate and autonomy support were associated with competence need, and competence need was associated with autonomous motivation in a positive way and with controlled motivation and amotivation in a negative way. On the other hand, autonomous motivation was positively associated with self-confidence, while amotivation was positively related to somatic and cognitive anxiety before a competition. Furthermore, there was a total mediation of competence need and autonomous motivation between task climate and self-confidence. In conclusion, these social factors favor self-confidence, and besides, these climates disfavor anxiety before a sport competition. (shrink)