SummaryData linking body mass index (BMI) and dental service utilization with oral and general health, quality of life, wellbeing, and mental health are lacking. Adult patients with clinically severe obesity attending a hospital‐based obesity service in Greater Western Sydney were invited to participate in a cross‐sectional survey that collected data on dental utilization and visiting patterns, dental anxiety, and oral health‐related quality of life (OHRQoL). General health data were obtained from participants' medical records. Of the 82 individuals who consented to participate, 81 (98.8%) completed the study questionnaire, and 74 (91.3%) answered additional screening questions related to their general wellbeing and mental health. Of the participants, 50 (61.7%) reported that their last dental visit was more than 1 year ago, 43 (53.1%) visited only as needed and 22 (27.2%) participants reported favourable dental visiting patterns. Twenty‐four (29.6%) participants reported high levels of dental anxiety, and low levels of OHRQoL compared with national data. Screening questions suggested low general wellbeing and poor mental health in this patient cohort. Within this group, BMI was not significantly correlated with any of the variables of dental service utilization, dental anxiety, OHRQoL, wellbeing, or mental health (p > .05). There was a negative correlation between dental anxiety and dental utilization (p < .05). Patients with clinically severe obesity reported poor dental utilization, low OHRQoL, and high levels of dental anxiety. This study highlighted the frequency of medical complications, lack of wellbeing, and poor mental health, which were evident in this cohort and may complicate dental management.