Traditionally, teacher credibility has been influenced by how others perceive them. However, exploring teachers' own perceptions of their credibility through the observation of learner behaviour may prove to be meaningful to teacher credibility. The aim of this study was to explore Intermediate Phase beginner teachers' perceptions of their own credibility based on displayed learner behaviour in their classrooms. This qualitative study was presented through a case study research design. Eight Intermediate Phase beginner teachers were purposively selected. The data collection techniques used were interviews and observations. Semi-structured interviews and a researcher journal were used as data collection instruments. The data were analysed using inductive thematic data analysis. The conceptual framing of this study was underpinned by a modified theoretical model developed by McCroskey, Valencic and Richmond (2004). The findings showed that teachers' perceptions of their own credibility were fluid as they engaged with various learners' behaviour, which was used as a form of feedback during lessons and this feedback impacted teachers' reactions and decisions to classroom situations. Ultimately, teachers' perceptions of their own credibility focused on their immediacy, trustworthiness, competence and dynamism displayed in their practices.