48 patients with chronic mechanical neck pain (CMNP) were randomized to either a single-level thoracic manipulation (STM) (T6-T7) group, a multiple-level thoracic manipulation (MTM) group, or a control group. The purpose of the study was to compare these two thoracic spine manipulation techniques to each other and to a control group in terms of cervical range of motion (CROM), visual analog scale (VAS), and Thai version of the Neck Disability Index (NDI-TH) at 24 hour and 1 week post-treatment follow-ups. Results indicated that neck disability and pain levels were improved in both manipulation groups when compared to the control group. Furthermore, CROM in flexion and left lateral flexion were improved in the STM group at 1 week follow-up compared to the control group, and CROM in right rotation was superior at 24 hours in the MTM group, when compared to the control group. No significant disparity was found in neck disability, pain level at rest, and CROM between the two thoracic manipulation groups.