Background: Oral hygiene behaviours as well as dietary habits before bed can affect children’s dental health resulting in higher prevalence of dental disease. Dental disease can affect children’s health, development and even school performance. If left untreated, dental disease can progress and it can lead to extractions under general anaesthetic causing further distress for children and families. Consistent and appropriate oral hygiene behaviours and dietary habits can prevent dental diseases from occurring in the first place. Objective: This cross-sectional study examines the relationship between oral hygiene behaviours, dietary habits around bedtime and children’s dental health. Methods: A total of 185 parents with children between the ages of 3 and 7 years from deprived areas participated in the study. Data on bedtime routine activities were collected using an automated text-survey system. Children’s dental health status was established through examination of dental charts and dmft (decayed, missed, filled teeth) scores. Results: In total, 52.4% of parents reported that their children’s teeth were brushed every night. The majority of children (58.9%) had dmft scores over zero. In total, 51 (46.7% of children with dmft score over 0 and 27.5% of all children) children had active decay. The mean dmft score for those experiencing decay was 2.96 (SD = 2.22) with an overall mean dmft score of 1.75 (SD = 2.24). There were significant correlations between frequency of tooth brushing, frequency of snacks/drinks before bed and dmft scores (r = −0.584, p < 0.001 and r = 0.547, p = 0.001 respectively). Finally, higher brushing frequency was associated with a lower likelihood of a dmft score greater than 0 (Exp(B) = 0.9). Conclusions: Despite families implementing oral hygiene behaviours as part of their bedtime routines those behaviours varied in their consistency. Results of this study highlight the need for additional studies that consider bedtime routine-related activities and especially the combined effects of oral hygiene practices and dietary habits due to their potentially important relationship with children’s dental health.