Self-Determination Theory (SDT) is a sociocultural motivational theory that has been extensively applied within schools as a means of developing teachers’ evidence-based practice, where the satisfaction of three basic psychological needs for relatedness, competence and autonomy has positive impacts upon students’ motivation to engage with classroom-based learning activities. SDT has proved to be an effective theory for suggesting why selected key classroom-based behaviours and variables influence the students’ engagement more than others. Whilst SDT emphasizes the centrality of autonomous motivation to students’ engagement with scientific learning, it may be such engagement is more likely to be an outcome of students’ perceived competence and teacher-student relationship quality. This potential outcome was explored through focus group interviews with 70 students, aged between 9 and 13. The responses consistently revealed key common variables that the students regarded the quality of the teacher-student relationship as being influential upon their perceptions of the teacher’s effectiveness at enhancing students’ perceived competence as opposed to satisfying any wish they had for their teacher to be autonomy-supportive. Such perceptions were consistently self-reported as being influential upon their engagement with, in this case, science-based learning activities.