Oral exercises provided by healthcare professionals have improved functional outcomes in various patients, such as cancer patients, post-stroke patients, and elderly patients. Among several patient education methods, the diagram is helpful to supplement written and oral information for those limited in their ability to read. Therefore, the diagram must be a more universal and comfortable tool to provide patient education in to a broad population. This study aimed to modify and design a self-instruction oral exercise diagram for Thai patients and evaluate the quality of the oral exercise diagram. The certified Japanese-Thai interpreter translated and re-translated the oral exercise diagram in our study to ensure the critical message and slightly modified it for readability. According to the pilot study, we altered the illustration for the Thai context. Nine invited experts involving oral care for the elderly have evaluated the oral exercise diagram's content using the Agency for Healthcare Research and Quality's Patient Education Materials Assessment Tool for printable materials (PEMAT-P) via electronic survey. The data analysis uses descriptive statistics. The median understandability (100%), actionability (100%), and overall scores (95.83 %) from the PEMAT-P survey support the diagram's utility for patient education. The results showed that our newly modified patient education diagram for selfinstruction on oral exercise provides practical and easy-to-follow patient information to improve oral function, particularly in the elderly.