Eighty-nine patients with moderate-grade adolescent idiopathic scoliosis were included, with 45 receiving a nighttime brace and 44 receiving a full-time brace. The primary outcome was curve progression to a Cobb angle ≥ 45°. Secondary outcomes included the rate of surgery, in-brace correction percentage, and radiographic parameters. Outcomes were assessed up to a median of 33 months, with a mean total follow-up of 94 months. Overall, the results of the study revealed no significant difference in curve progression between groups and a similar mean time to surgery. However, there was a non-significant trend toward more surgeries in the nighttime group. These findings suggest that nighttime bracing, with the option to transition to full-time bracing upon progression, may be a viable alternative to full-time bracing, offering similar effectiveness in preventing progression with potentially better compliance.