BACKGROUND: Chronic non-specific neck pain is related to limited cervical mobility, impaired function, neck muscles myofascial pain syndrome, and stress at work. The aforementioned factors are strongly related and may lead to a negative impact on health-related quality of life. There are some effective conservative Physical therapy interventions for treating chronic non-specific neck pain. Currently, Deep Dry Needling is emerging as an alternative for improving symptoms and consequently, the quality of life in patients with chronic non-specific neck pain. The purpose of the study was to examine the effectiveness of Deep Dry Needling of myofascial trigger points on health-related quality of life improvement, as a secondary analysis, in people with chronic non-specific neck pain. METHODS: A randomized parallel-group blinded controlled clinical trial was conducted at a public Primary Health Care Centre in Madrid, Spain, from January 2011 to September 2014. One hundred thirty subjects with chronic non-specific neck pain and active myofascial trigger points in neck muscles were randomly allocated into two groups. Subjects in the intervention group (n = 65) were treated with Deep Dry Needling in active myofascial trigger points plus stretching in neck muscles; Control group (n = 65) received only stretching. Both interventions lasted 2 weeks, 2 sessions per week. Health-related quality of life was measured with Short Form-36 (SF-36), in 5 assessments: at baseline, after intervention period; and at 1, 3 and 6 months after intervention. RESULTS: For both groups, SF-36 mean values increased in all dimensions in every assessment. Significant differences (p < 0.05) were found in favor of the intervention group for all dimensions at the last assessment. For some dimensions (physical function, physical role, social function and vitality), the evidence was more consistent from the beginning. CONCLUSIONS: Deep Dry Needling plus stretching is more effective than stretching alone for Health-related quality of life improvement, especially for physical function, physical role, social function and vitality dimensions, in people with non-specific neck pain. TRIAL REGISTRATION: Current Controlled Trials ISRCTN22726482 . Registered 9 October 2011.