Purpose To compare the effects of postural corrective and Schroth-based three-dimensional exercises on thoracic kyphosis angle (TKA), lumbar lordosis angle (LLA), balance and quality of life (QoL) in individuals with postural kyphosis. Methods This was a single-blind randomized controlled clinical trial with a total of 63 subjects (57 women, 6 men) with TKA of 40°. Subjects were separated into three groups: postural corrective exercise group (PCEG), Schroth-based three-dimensional exercise group (SBEG) and control group (CG). Participants in the exercise groups participated in the exercise program twice a week for eight weeks under the supervision of a physiotherapist: CG performed no exercise but was generally informed. The primary outcome variable was TKA. Secondary outcome variables were LLA, balance and QoL. Results After the functional exercise programs, TKA (mean change for PCEG, SBEG: −9.71, −14.76, p < 0.001), static postural stability index overall (−0.22, −0.40, p < 0.05), and QoL (−0.41, −0.37, p < 0.001) significantly improved in both training groups compared with CG. The LLA (−3.95, p = 0.003) was significantly lower in the SBEG group than in CG. Conclusion This study demonstrated that Schroth-based three-dimensional exercises are an effective treatment for individuals with postural kyphosis and have a large effect size that improves TKA, LLA, balance and QoL. Clinical trial registration number: NCT03706495 Implications for rehabilitation Eight weeks of postural corrective or Schroth-based three-dimensional functional exercise programs are effective in addressing thoracic kyphosis angle (TKA), balance, and quality of life in individuals with postural kyphosis. An eight-week Schroth-based three-dimensional exercise program was more effective than postural corrective exercises in improving TKA, lumbar lordosis angle, and balance for patients with postural kyphosis. Schroth-based three-dimensional exercise programs could promote balance and spinal health in young adults with thoracic kyphosis.