Forty-one patients with mechanical neck pain classified in the "mobility" category were randomized to receive thoracic spine manipulation (TSM) (n=21) or sham manipulation (n=20). The primary outcomes were neck pain during rotation (Numerical Pain Rating Scale, NPRS) and subjective improvement (Global Rating of Change, GROC). Secondary outcomes included NPRS at rest, Neck Disability Index (NDI), and cervical and thoracic spine range of motion (ROM). Outcomes were assessed at baseline, immediately post-treatment, and at 1 and 4 weeks. Overall, TSM significantly reduced NPRS during neck rotation and improved cervical and thoracic ROM and NDI scores compared to sham manipulation (p < 0.001). These improvements persisted over 4 weeks. These findings suggest that TSM is a beneficial intervention for patients with mechanical neck pain in this subgroup.