Background: This study aims to investigate the effects of dry-needling treatment on the quality of life in athletes with myofascial pain syndrome (MPS). Methods: The participants included in the study were 50 athletes (38 males and 12 females) diagnosed with MPS. The treatments were carried out in four sessions, 5/7 days apart on 55 muscles in total. A 36-item health survey (SF-36) was implemented to determine the participants’ quality of life. The chi-square test was used to determine the differences between measurements. Results: Dry-needling treatment has a positive influence on self-perspective of physical functioning (p = 0.011, on average), physical problems (p = 0.001, on average), emotional problems (p = 0.004, on average), social functioning (p = 0.001, on average), pain (p = 0.001, on average), and mental health and vitality (p = 0.001, on average) in athletes with MPS. The only quality-of-life dimension not influenced by the dry-needling treatment is the general health perception (p = 0.340, on average). Conclusions: Dry-needling therapy has positive effects on the perception of quality of life in athletes with MPS.