Ninety patients with non-specific chronic neck pain were randomized to receive cervical spine (Mulligan Concept) and diaphragm manual therapy plus breathing re-education (EG1; n=30), cervical spine manual therapy plus sham diaphragmatic therapy (EG2; n=30), or conventional physiotherapy (CG; n=30). The primary outcome of interest was active cervical spine range of motion (flexion/extension, bilateral side-flexion, bilateral rotation). Secondary outcome was forward head posture (craniovertebral angle). Outcomes were assessed pre-treatment, immediately post-treatment (after 10 sessions/1 month), and at 3 months. Overall, the results of the study revealed larger ROM gains with EG1 versus CG in five of six directions (except flexion) and versus EG2 for extension, with improvements generally maintained at 3 months; craniovertebral angle improved similarly across groups. These findings suggest that integrating diaphragm-focused manual therapy and breathing re-education augments cervical mobility beyond conventional care, though posture change (CVA) may require additional strategies.