The aim of this case report was to present the orthodontic treatment of an adult with spaced dentition, Class III malocclusion, and open-bite tendency. A 28.4-year-old adult woman was concerned about the unesthetic appearance of her spaced dentition localized at both upper and lower arches while smiling. She had a mild tongue thrust, hypertropic upper frenum, and mild speech difficulty while pronouncing "s". Her profile was straight with prominent lips. Molar relationship was Class III on both sides. Anterior teeth were in an end-to-end relationship. Lower dental midline was deviated to the left side. Cephalometric analysis revealed a skeletal Class III relationship with hyperdivergent facial pattern. The treatment plan included myotherapeutic exercises for the tongue thrust habit and a diagnostic set-up for closure of diastemas. A strict retention protocol was followed combined with gingivoplasty, fiberotomy, and frenectomy procedures. All spaces were closed successfully, adequate overbite and overjet relationships were obtained, and tongue thrust habit and speech difficulty while pronouncing "s" were eliminated. Clinical and cephalometric results indicated the maintenance of the treatment outcome at 6-months post-retention period.