It is well documented that the personal qualities of the counsellor are important to counselling efficacy. This behoves counsellor education programs to identify suitable applicants for their programs and to develop cogent methods of assessing students' personal qualities; however, despite the increasing interest demonstrated by researchers in personal qualities, little consensus is found on the key personal qualities of counselling practitioners. This lack of consensus is compounded by a lack of robust assessment tools for assessing the development of those qualities. In Australia, counsellors continue to advocate for government recognition as credible mental health providers, with concerns expressed regarding a lack of consistent minimum education standards across the peak associations. Discussion regarding minimum education standards is ongoing, and within this context, the researcher is interested in what differentiates counsellor education from that of other mental health professions. One clear difference seems to be a greater emphasis on the person of the counsellor, including the development of their personal qualities (referred to as personal development) in counsellor education. As an educator, the researcher is also interested in how personal qualities are being developed and assessed in counselling programs, and what determines these approaches to assessment. Existing research on counsellor education in Australia is minimal, which motivated this investigation into the key qualities required of counselling students, approaches to assessing these qualities, and factors determining these approaches to assessment. This investigation was conducted within a critical realist framework because the research questions did not sit well in either a positivist or constructivist paradigm. Critical realism acknowledges that reality is layered and complex, and as such, is well suited to research questions that seek to explain outcomes such as the factors that determine approaches to assessing students' personal development. The research design was a collective case study, using 10 PACFA-accredited counsellor education programs as the collective case. In-depth, semi-structured interviews were conducted with three personnel from each program and then analysed using grounded theory coding. Seven key personal qualities were identified: self-awareness, openness, interpersonal skills, emotional stability, cognitive complexity, professionalism, and personal maturity. Further analysis of these interviews and a supporting document analysis of counselling program documents revealed that these key qualities were assessed across the course of students' education using a range of explicit and implicit approaches to assessment. Abductive reasoning was used to hypothesise explanations for surprising outcomes in the data analysis, and, in particular, the balance of explicit and implicit approaches to assessing students' personal development. In addition to the prevalence of ambiguous language and overlapping conceptualisations, structural mechanisms identified as influencing the assessment of students' personal development include a) the program's counselling philosophy and the clarity with which that philosophy is articulated, b) the intentionality of counselling educators, c) institutional philosophy and/or priorities, and d) Australian higher education (HE) regulations. The way and extent to which programs were influenced by institutional philosophy/priorities and the Australian HE regulations was found to be context dependent. The results of this research have implications for counsellor education programs and program accreditation standards. Further clarity regarding the personal development component of counsellor education is required from professional bodies responsible for program accreditation, along with more guidance as to the types of evidence required to demonstrate that standards are being met. Such guidance could be drawn from the outcomes of this investigation, including the importance of counselling philosophy to personal development, and the significance of clarity and coherence to all facets of program development and delivery. A more intentional focus on personal qualities would be in line with the United States (Council for Accreditation of Counselling and Related Education Programs, 2015) and British standards (British Association for Counselling and Psychotherapy, 2020), and could be a clear point of differentiation for Australian counsellor education from other mental health disciplines. Recommendations regarding key qualities for entering the counselling profession include operationalising terminology, acknowledging the importance of cognitive complexity, and using personal maturity as a global construct, with other qualities considered subdimensions. Recommendations regarding the assessment of students' personal development include education programs clearly articulating their counselling philosophy, mapping personal development goals, and increasing support for counselling educators. Further research is also recommended to gain more insight into the interaction between educators' agency and intentionality.