Background and Aims A flat foot is associated with complications, such as pain, fatigue, and balance decline. The present study investigated the effect of 8 weeks of foot reflexology massage on balance, foot arch, and pain in girls aged 14 to 18 years with flat feet. Methods In this quasi-experimental research, 30 girls with flat feet (mean age: 15.1±1.1 years, mean height: 156.1±2.2, and mean weight: 47.3±2.2 kg) voluntarily and conveniently were selected and randomly divided into two equal experimental and control groups. The massage program consisted of eight weeks (three sessions per week) of foot reflexology massage on the entire sole of both feet, in which two to three relaxation techniques were used in each session, according to the subject’s condition, for six minutes. Twenty-four hours before and 24 hours after the end of the massage therapy protocol, foot arch, dynamic balance, static balance, and pain intensity were assessed using the index of navicular drop test, star excursion balance test, balance error scoring system, and visual analog scale, respectively. Data analysis was done with an analysis of covariance at a significance level of 0.05. Results The results showed that reflexology massage significantly affects static balance (P=0.0001) and pain intensity (P=0.0001) of young girls with flat feet. However, no significant effect was observed on the arch of the foot (P=0.38) and the dynamic balance (P=0.36). Conclusion Reflexology massage improves the proprioceptive information of the skin. Accordingly, it has improved static balance and reduced the pain intensity of girls with flat feet.