Objectives Workplace-based competency is increasingly considered fundamental to patient safety and quality healthcare. The aim of the present study was to identify and describe physiotherapists’ perceptions of workplace competency. Methods The present study was a mixed-methods cross-sectional observational study. Thematic and descriptive analysis of qualitative and survey data were undertaken. Forty-six physiotherapists employed at a metropolitan acute public hospital participated in interviews or focus groups; a subgroup of 31 participants also completed an online survey. Results Five main themes were identified: (1) despite the availability of workplace learning opportunities and supports, less-experienced staff reported limited confidence; (2) assessment and feedback around workplace competency was limited, predominantly informal and unstructured, with less than half of the cohort (42%) agreeing feedback received was useful for improving their workplace skills; (3) practicing within individual scope is an important aspect of workplace competency as a physiotherapist; (4) most (81%) agreed it was important for them to self-determine their learning and development goals, and they relied primarily on informal discussion to achieve these goals; and, (5) physiotherapists felt motivated regarding workplace learning, with 97% interested in developing their workplace skills however, nearly half (45%) did not feel they had sufficient time to do so. Conclusions The perceptions of physiotherapists working in a metropolitan acute public hospital are reflected in five themes. These themes elucidate how workplace competency is supported, maintained and developed among physiotherapists in this setting. These themes also highlight key challenges of workplace learning faced by this cohort of physiotherapists and allude to methods that may assist with improving feedback mechanisms and knowledge acquisition. What is known about this topic? Studies investigating employee perceptions around workplace competency, knowledge, skills and learning are found across a range of industries. Workplace-based competency is increasingly considered fundamental to patient safety and quality health care. There is little known about physiotherapists’ perceptions of workplace competency. What does this paper add? This study has identified and described themes around physiotherapists’ perceptions of their workplace knowledge and skills. What are the implications for practitioners? The themes identified provide support for the development, implementation and evaluation of a workplace-based competency framework for physiotherapists.