This study aimed to determine the effect of a smartphone-based medication education program to help mothers safely administer medication to their children at home. A quasi-experimental, non-equivalent control group, pretest-posttest design was utilized. There were 33 participants in the experimental group and 30 in the control group. The experimental group participated in the KidsMedi program for 6 weeks. The experimental group, receiving the KidsMedi program, had a statistically significant higher perception of antipyretic analgesics and higher eHealth literacy than the control group. The medication education program developed in this study is a mobile Web-based program. It is an effective program for mothers to improve their knowledge about administering drugs to children at home. This program is not affected by time and place, allowing repetitive self-directed learning. Nurses can utilize this program in daycare centers, schools, hospitals, communities, and public institutions to educate parents about safe medication for children.