Objectives: This study was carried out to develop a suitable oral health promotion program to determine the knowledge, attitude, and practice among patients visiting the Mataniko Dental Clinic (MDC), Honiara City. Materials and Methods: A cross-sectional study was conducted among 1050 patients aged 18–45 who attended MDC, Honiara City, from July 2021 to September 2021. A 26-item questionnaire was used to evaluate their oral health knowledge, attitude, and practice. The questionnaire includes patient’s demographic information, knowledge, attitudes, and behavioral practice. Results: Oral health-related knowledge among the study participants was high. However, only 1 in 5 (24%) never visited a dentist. More than half (58%) of the participants visited the dental clinic because of toothache. Over 2 in 3 (63%) participants received professional advice. Four in 5 (83%) participants had toothpaste; however, only 33% brushed their teeth twice a day. Interestingly, more than half (58%) of the participants were unsure of the toothpaste used to brush their teeth. Conclusion: While the level of knowledge was high, this was not translated into their dental healthcare attitude and practice. Therefore, an oral health promotion program is needed to motivate and promote the importance of dental health and the participant’s well-being.