ObjectiveThe purpose of this study was to develop and evaluate the effectiveness of using e‐learning on smartphones to provide dental hygiene education on dental treatment procedures.MethodsThis was a randomized controlled trial. Two‐hundred ninety‐three dental hygiene students in four universities, one junior college and one technical school took a preliminary examination, and based on the results, participants in each school were randomly divided into two groups, a test or control group. Both groups took pre‐ and post‐examinations at a 4‐week interval. The test groups learned dental treatment procedures and four‐handed techniques with interactive learning materials using smartphones. The learning materials allowed them to watch videos of dental treatments. The control groups were not provided any learning material.ResultsResults of all schools combined showed that the changes from pre‐ to post‐examination scores in the test groups were significantly higher than those of the control groups (p < .05). Post‐examination scores were significantly higher than pre‐examination scores in the test groups in all schools (p < .05). Also, post‐examination scores of the test groups were significantly higher than those of the control groups (p < .05). The changes from pre‐ to post‐examination scores in the test groups of two schools were significantly higher than those of control groups (p < .05). Post‐examination scores of the control groups in two schools were significantly higher than pre‐examination scores (p < .05).ConclusionsLearning dental treatment procedures through e‐learning on a smartphone was effective in developing participants’ understanding of dental treatment procedures and four‐handed techniques.