Background: Oral disease is one of the most prevalent chronic health conditions affecting children. Twice-daily toothbrushing is recommended to promote good oral health; however, a large proportion of Australian families are not meeting this recommendation. Aim: This study aimed to identify important barriers to regular toothbrushing for young children. Design: In this study, 239 parents of 0- to 4-year-old children completed an online survey that investigated child, family, and parent factors associated with child toothbrushing. Hierarchical linear regression was used to identify predictors of toothbrushing frequency in children and perceived difficulty of the task by parents. Results: We found that parent factors, specifically oral health knowledge, were the most significant predictors of toothbrushing frequency. Conversely, parent factors did not contribute significantly to the prediction of perceived difficulty of toothbrushing once family and child factors were taken into account. Oral health knowledge and use of routines were identified as the most important predictors of toothbrushing frequency, whereas resistant child behaviour and household organisation were found to be the most important predictors of perceived difficulty of regular toothbrushing. Conclusions: The findings of the study have implications for behavioural interventions to support parents, as well as directions for future research.