In 2017, the Royal Commission into Institutional Responses to Child Sexual Abuse recommended reforms to the law of competence of child witnesses. We examined Australian judges’ practices in assessing children’s competence to give sworn evidence. Trial transcripts from 56 victims revealed that 64% were posed competence questions, with fewer to older children. The most frequent manner of posing such questions was to ask children to evaluate the morality of truths and lies. Most questions were yes-no format, and children nearly always answered these satisfactorily. When questions were ‘wh-’ format, children provided a satisfactory response only 51% of the time. Only nine children testified unsworn, and they were asked more than twice as many competence questions as sworn children. Competence inquiries have been challenged for underestimating children’s abilities, and because responses to questions about truths and lies are not predictive of behaviour. We discuss how reforms could be implemented.