Purpose: To evaluate the effectiveness of an oral health mobile application on the oral health knowledge, behavior, and practices (KBP) of child-parent dyads. Methods: This was a pre-post, single-arm, hospital-based pilot study. Fifty-two dyads were assessed for KBP using a self-structured questionnaire. The oral hygiene of children was evaluated using the plaque index (PI). The Healthy-Smile Swasth-Muskaan mobile application was installed on the phones of participants, and they were encouraged to use the application regularly. After one month of the app instalation, post-KBP and PI were assessed. Results: A significant improvement was seen in the parents' total knowledge, behavior, and oral hygiene practices of the children (P<0.001). A significant reduction was observed in the mean plaque scores of the children (P<0.001). Conclusions: The Healthy-Smile Swasth-Muskaan mobile app is associated with improved oral health knowledge and behavior of the child-parent dyads and im- proved oral hygiene of children. Further randomized clinical trials are needed to determine the impact of mobile apps on the oral health knowledge, behavior, and practices of parents and children.