Background: This study aimed to evaluate the stress distributions in the periodontal ligament (PDL) and alveolar bone of immature maxillary central incisors with regenerative endodontic treatment (RET) and natural immature teeth under different orthodontic forces using three-dimensional finite element analysis (FEA). Methods: 3D models of natural immature and RET-treated central incisors were created using SolidWorks software. In the RET model, a 3 mm MTA plug was added to the cervical root region, and a regenerative tissue simulation was added to the root canal. Dentin, PDL, and bone were considered homogeneous, isotropic, and linear elastic. Tetrahedral meshing and convergence analysis were performed. Three different loading scenarios of 1 N were applied from the bracket level: mesial translation, mesio-buccal rotation, and palatal tilt. Maximum principal tensile and compressive stresses were calculated in PDL and bone. Results: Similar maximum tensile stress values (0.110–0.151 MPa) were found in both natural and RET-treated teeth under all loading scenarios. Stresses were concentrated in the crestal regions of the PDL and corresponding bone areas. In RET models, stress in the PDL was more widely and homogeneously distributed, while bone stress patterns remained largely similar between models. Conclusion: RET-treated immature teeth exhibit similar stress distribution to natural teeth under orthodontic forces. These results support that light and controlled forces can be safely used on RET-treated teeth; however, long-term follow-up studies are required for clinical confirmation.