Background: Epilepsy is a neurological condition that around 70 million people worldwide have. Phenytoin is the most common anti-epileptic therapy for controlling epilepsy and preventing its recurrence. The side effect of phenytoin therapy includes gingival overgrowth which often causes psychological and aesthetical problems, interferes with normal mastication, and worsen the gingival inflammation. There are surgical and non-surgical options to treat phenytoin-induced gingival overgrowth, one of the non-surgical options to treat phenytoin-induced gingival overgrowth. One of the non-surgical treatment for phenytoin-induced gingival overgrowth is folic acid  supplementation, which has been studied to prevent the adverse side effects of phenytoin therapy despite the variative results. Objective: To discover the current theory depiction about the effect of folic acid supplementation on gingival overgrowth due to phenytoin therapy. Method: The type of the research is descriptive observational research and method of scoping review. Journals obtained using PCC (population, concept, and context) with population of patients on phenytoin therapy, using concept of preventing phenytoin-induced gingival overgrowth using agent supplementation, and context of folic acid. The inclusion and exclusion criteria filtered by boolean search on two databases, PubMed and Google Scholar from 1987 to 2020. Results: A total of 5 journals found and all of them are included in a table with the results of the studies discussing about folic acid supplementation in phenytoin-induced gingival overgrowth. Conclusion: Folic acid supplementation was found to delay the onset, reduce the incidence and severity as well as the risk of recurrence after gingivectomy on phenytoin-induced gingival overgrowth.