Purpose: To examine oral health related behaviours in relation to anxiety, depression and attention deficit hyperactivity disorder (ADHD). Materials and Methods: This study included 364 subjects (195 female, age range 19-65 years; 169 male, age range 18-64 years). A psychological evaluation was performed using Beck's anxiety, Beck's depression and ADHD scales. A separate questionnaire covering oral health behaviours, including parafunctional habits, dental visits and toothbrushing frequency, was given to the subjects and completed before the clinical examination. The numbers of decayed, missing and filled teeth were recorded and the status of the subject's periodontal health was determined clinically using periodontal probes and panoramic radiographs. Results: There were significant differences in the gender, level of education, level of income, household size, parafunctional habits and number of missing teeth in those with anxiety and depression (p 0.05) vs those without. Females and subjects with parafunctional habits and lower education and income level presented higher anxiety and depression scores. ADHD was associated negatively with household size and positively with dental visits and toothbrushing frequency (p 0.05). The results of structural equation modeling (SEM) revealed that anxiety, depression and ADHD were indirectly related to missing teeth and periodontal status: subjects with higher depression and anxiety scores had more missing teeth and worse periodontal health. However, there was no association between psychological factors and decayed teeth or toothbrushing frequency. Conclusions: Anxiety, depression and ADHD can result in poor oral hygiene, thereby having indirect, adverse effects on the periodontal health status of affected individuals. Although the frequency of dental visits seemed to be related to anxiety and ADHD, the frequency of toothbrushing showed no such association. Keywords: anxiety, behavioural science, depression, oral health, psychosocial aspects of oral health