Background: Chronic non-specific neck pain (NP) is a common musculoskeletal disorder recognized for its high rates of disability and economic losses, ranking second in musculoskeletal conditions after low back pain. There are several effective physical therapy interventions to treat chronic nonspecific NP, among which there is the low-level laser therapy. High-intensity laser therapy (HILT) is a recent treatment proposed to reduce musculoskeletal pain; however, there are few studies that showits effects in reducing NP. The aim of this study is to evaluate the effect of high-intensity laser therapy on pain intensity in patients with chronic nonspecific NP. Methods: This is a 2-arm, randomized, placebo-controlled trial with blinded evaluators. The research will be carried out in the laboratory of physical agents at the Andrés Bello University, Campus Casona de las Condes. Eligible participants include the entire internal and external community associated with Andrés Bello University suffering from chronic non-specific NP. Participants will be stratified by sex and randomized into 2 groups: group 1 (HILT and stretching exercises) and group 2 (shamHILT and stretching exercises). Treatments will be performed twice a week for 4 weeks with 3 assessments: before treatment (T0), at the end of treatment (T1), and 12 weeks after treatment (follow-up) (T2). The main outcomeswill be pain intensity at rest, pain intensity at movement, and pain pressure threshold. Secondary outcome measures will include neck range of motion and neck disability. Discussion: In this study, HILT's effects on patients with non-specific NP will be compared to those of a sham laser intervention. This RCT will offer new evidence regarding the potential benefits of HILT in terms of pain intensity, range of movement, and disability in people suffering with non-specific NP. Trial registration: NCT05689788

This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-Non Commercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.