•Higher levels of TSE related to more positive and encouraging feedback.•Higher levels of TSE related to positive attributions towards low effort students.•Teachers with higher levels of TSE may engage in an intrapersonal causal search.•Teachers with higher TSE levels may consider their part in student underachievement. This study of 122 British secondary teachers investigated the relationship between teacher self-efficacy and teachers’ causal beliefs towards students with and without specific learning difficulties. Results found that teachers reporting higher levels of teacher self-efficacy provided more positive feedback to all students, regardless of students’ ability levels, effort expenditure, or the presence of specific learning difficulties. Additionally, teachers reporting higher levels of teacher self-efficacy felt less frustration, more sympathy, and held lower expectations of future failure towards students who expended low effort. The findings suggest that teachers with higher levels of teacher self-efficacy may undertake a teacher-intrapersonal causal search to explain student underachievement, in comparison to teachers with lower levels of teacher self-efficacy who may undertake an interpersonal causal search.