Dietitian clinical decision making in the acute care setting likely incorporates a practitioner’s clinical judgement to effectively support patient care. The term ‘dietitian clinical judgement’ is well used in clinical practice, yet is poorly defined and often used interchangeably with other concepts. The aim of this research was to describe the nature of dietitians’ clinical judgement in the acute care setting. Methods: A qualitative design within the interpretative paradigm was used guided by principles of philosophical hermeneutics. Dietitians with at least 3 years experience were invited to participate in two 60-min in-depth semi-structured interviews which were recorded, transcribed and interpreted using hermeneutic principles. A reference group was used to increase rigour and further interpretation of the findings. Results: Ten dietitians participated in the interviews and five of these same participants in the reference focus group. The findings revealed clinical judgement to be a sophisticated practitioner dependent meta-reasoning process that helps the dietitian manage complexity, guide interpersonal interactions and individualise patient care. It is characterised by tacit and efficient use of various reasoning strategies reliant on the dietitian’s clinical experience, used to synthesise and weigh up various types of information and knowledge with respect to delivering context-relevant care. Conclusions: Dietitian clinical judgement is a necessary part of clinical decision making that extends beyond logical or critical thinking. It facilitates a person-centredness to patient care and professional relationships that are key dimensions to dietitian clinical decision making. These findings provide training and professional development insights to managers, educators and supervisors.