Coalitions of the foot are relatively uncommon abnormalities, occurring in approximately 1% of the population. Talocalcaneal and calcaneonavicular are the most common types of coalitions. Coalitions in the forefoot, however, are rare, with only a small number of case reports in the literature. We report on a unilateral, symptomatic coalition between the first and second metatarsals in a 12-year-old girl who presented with a several-month history of intermittent medial-sided, dorsal forefoot pain and difficulty with shoe wear. Her preoperative examination was notable for a firm, nontender dorsal medial forefoot mass centered between the first and second metatarsals. While the first metatarsal head was level with the second metatarsal head in the sagittal plane, the metatarsals were rigidly fixed to one another. First metatarsal-medial cuneiform motion was reduced compared to the unaffected foot. Preoperative magnetic resonance imaging demonstrated a bony and cartilaginous coalition between the first and second metatarsals. Following resection, an immediate improvement was noted in motion between the first and second metatarsals, as well as the first metatarsal and medial cuneiform. In our patient, rigidity between the first and second metatarsals contributed to a stiff first ray with higher plantar pressures beneath the first metatarsal head with walking. The abnormal kinematics likely contributed to her medial forefoot pain with prolonged ambulation and sports activities. Prompt identification and resection of these less common coalitions affecting the forefoot allows symptomatic relief and restoration of normal kinematics.