This case report describes the clear aligner treatment of a 20-year-old woman presenting with mild crowding, Class I molar and canine relationships, and minor midline deviation. A personalized 3D plan with 20 upper and lower stages was developed, following a non-extraction approach integrating arch expansion and interproximal reduction. Each aligner was worn for 22 hours daily and changed every 10 days. The total treatment duration was 7 months. At completion, crowding and misalignment were fully corrected, achieving ideal overjet and overbite with properly aligned arches. Periodontal health remained stable throughout, demonstrating clear aligners as an effective, minimally invasive option for crowding correction in adult orthodontic patients.