Purpose: Based on person-context interaction, situational interest (SI) has been used to interpret students’ motivation in task engagement. Through two consecutive studies, the purpose of this research was to investigate the roles of forms of dyads (self-selected vs. ability), feelings of relatedness and perceived competence in eliciting students’ SI within the reciprocal teaching style. Method: The first study examined the role of dyad composition to determine how to group students to elicit high SI (self selected vs. ability dyads) and compared self-selected and ability dyads using repeated-measures of students’ SI, perceived competence and feelings of relatedness, with 99 students in a PE unit. Based on the results of this first study, demonstrating the benefits of the self-selected dyads, the second study aimed to investigate the role of feelings of relatedness and perceived competence in eliciting students’ SI within football (99 students) and gymnastics units (109 students) using MANOVAs and a cluster approach. Results: The first study’s results showed higher scores for SI, perceived competence and feelings of relatedness in favor of self-selected dyads compared to ability dyads. In the second study within selfselected dyads, the results showed a small effect of perceived competence and a stronger effect of feelings of relatedness on SI. Conclusion: To elicit students’ SI within the reciprocal teaching style, teachers should favor self-selected dyads. This paper highlights the importance of designing contexts where students can develop good peer relationships to increase SI. The implementation of self-selected grouping in PE is interesting since it is less time-consuming than other grouping strategies.