This study adopted a pragmatic qualitative research design to unpack high and low efficacy teachers' task analysis and competence assessment in the context of teaching low-achieving students. Nine secondary school English and Science teachers were recruited and interviewed. Results of thematic analysis show that helping students perform well in exams was identified by both the high efficacy teachers (HETs) and the low efficacy teachers (LETs) as the sacred task, but the HETs perceived more contextual support from school culture, school leaderships and collegiality than the LETs did. Although the HETs showed more confidence than the LETs in instructional strategies, classroom management and student engagement, both the HETs and LETs experienced struggles when their personality traits and beliefs were in conflict with required strategies or imposed regulations. Despite the LETs having a lower level of perceived competence, their hunger for learning reveals that their sense of efficacy could be enhanced if provided with courses that focus on coaching and mentoring experiences.