Poor performing students have been found to generally report unjustified high levels of confidence in their academic performance. The aim of this study was to elucidate the reasons students provide as justifications for their perceived academic performance in a chemistry test. As part of a larger mixed methods study, students enrolled in a foundation chemistry course (N = 91) were required to justify their level of confidence in the accuracy of their responses during a pre- and posttest set on a specific chemistry topic. The qualitative data was analysed for the purposes of the current study and is presented in this paper. The students’ responses shed light on the explanations students give as justifications for their confidence judgements and the influence of teaching on these explanations.