Isolated distal ulna epiphyseal plate injuries are very rare and are often associated with early epiphyseal plate arrest. A 13-year-old boy sustained an isolated minimally displaced Salter-Harris type II fracture of the left distal ulna following a fall from a bicycle. The fracture was reduced, and a long arm plaster cast was applied for four weeks. At the six-month follow-up, the patient presented with a painless, full range of movement of the left wrist, but on radiological examination, a mild shortening of the ulna was detected. We plan to regularly evaluate this patient until distal epiphyseal plate closure and surgically intervene if necessary. To our knowledge, this is the third Salter-Harris type II distal ulnar fracture ever reported, and the second treated nonoperatively. It was shown to be associated with a mild growth disturbance. Although Salter-Harris type II injuries are considered benign, surgeons should closely evaluate this rare type II isolated distal ulnar fracture and inform parents regarding possible future complications, which range from clinically insignificant cosmetic deformity to severe instability of the distal radioulnar joint, depending on the degree of shortening.