Background: Postural changes are considered a public health issue and have gathered significant interest in both research and clinical practice. Aims: To evaluate the effectiveness of Global Postural Reeducation (GPR) in improving postural changes and postural stability in healthy young adults. Additionally, this study aims to identify the main postural changes in the sample population. Methods: A longitudinal study was conducted with a sample of students (n = 38) from the 2nd and 3rd years of undergraduate programs at Coimbra Health School, divided into an experimental group (EG) with 20 subjects and a control group (CG) with 18 subjects. The EG underwent a GPR intervention, while the CG received no intervention. Postural changes were assessed using a 3D motion analysis system (Qualisys), and stabilometry was evaluated using a Bertec force platform. Results: At baseline (T0), the groups were homogeneous regarding sample characterization variables, as well as postural and stabilometric variables (p > 0.05). After four weeks of the intervention (T1), no significant differences were observed between the EG and CG for any of the variables studied (p > 0.05). However, within-group analysis for the experimental group revealed a significant difference (p = 0.04) in anterior-posterior velocity, indicating a reduction in this parameter from T0 to T1. In the control group, a significant difference was observed (p = 0.03) in the left knee valgus, indicating a reduction in valgus alignment. Conclusions: GPR does not appear to be effective in improving postural changes or center of pressure displacement in healthy young students.