Objective: To assess the caries experience and periodontal status of a group of Sri Lankan children with cerebral palsy (CP) and to correlate it with caregivers’ knowledge on oral hygiene/diseases. Materials and methods: Ninety-three children with CP aged between 3 years and 18 years were included in the study. An oral examination was carried out to assess the dental caries and periodontal status by calibrated, trained dental surgeons. An interviewer-administered questionnaire comprising 10 questions was used to assess the oral health-related knowledge of caregivers. The results were analyzed statistically using Chi-square test (p < 0.05). Results: The prevalence of caries in permanent and primary dentition was 10.75% and 55.91%, respectively, while 100% showed gingivitis in varying severities. Dental history revealed that only 6% of the children brushed their teeth alone. When the knowledge was tested, majority of caregivers (93.5%) knew that children should visit a dentist even without any complaint at least once in every 6 months; in contrast, 62% had never visited a dentist. Caregivers’ level of knowledge is significantly correlated with poor oral health, as children with high level of caries in permanent dentition (p = 0.025) and severe gingivitis (p = 0.013) were most often accompanied by individuals with poor/moderate oral health-related knowledge. Conclusion: Although majority of caregivers have moderate level of knowledge related to oral health, it does not invariably mean that they apply this knowledge to maintain good oral health in children. As gingivitis was observed in all patients, caregivers require instructions on how to perform good plaque control to maintain good periodontal health and reduce caries. Therefore, more educational programs are required to motivate caregivers to effectively practice oral health-related habits.