Objective: This study investigated the correlation between thoracic spine sagittal mobility and lung function among physical therapy students. Materials and methods: A total of forty-six students from Deraya University ages ranged from 19-24 years were enrolled in one group to study the correlation between sagittal spinal variability in the thoracic region and lung function among physical therapy students by using a Spinal Mouse device to measure the thoracic spine sagittal mobility and spirometer device to assess lung function (forced expiratory volume FEV & forced expiratory volume / forced vital capacity FEV1/FVC). Results: There was a moderately negative correlation between FVC, FEV1, and posture from the fixed neutral position (r = -0.643, p = 0.001) and (r = -0.570, p = 0.001) respectively but was not significantly correlated with posture from neutral to flexion or neutral to extension. The correlation between the FEV1/FVC and posture was moderately negatively correlated with posture during movement from neutral to flexion (r = -0.322, p = 0.029) but not significantly associated with posture from neutral to neutral to extension. Conclusion: It can be concluded that habitual position leads to segmental hypomobility of the thoracic spine which may affect pulmonary function among physical therapy students.