Objective The aim of this study was to investigate the effect of radial extracorporeal shock wave therapy (rESWT) on the treatment of trigger finger. Methods Eighteen patients, who were 2nd grade according to Quinnel classification and diagnosed with trigger finger, were included in this prospective cohort clinical study. The study consisted of only the experimental group and no control group. Eighteen patients with trigger fingers were applied to ten sessions, twice a week, for five weeks of rESWT (2000 impulses, 2 bar, 10 Hz). Pain scores (Numeric Pain Rating Scale), general functional capacity (Quick-DASH), range of motion, grip strength, and pinch strength were evaluated before treatment, after treatment, and three months after the treatment. Results Evaluation of ten sessions of rESWT that applied twice a week, for five weeks, was made before treatment, after treatment, and three months after the treatment. Statistical analyses were performed with the Friedman test. As a result of the analyses, there was a decrease in the pain levels (p < 0.001) and increase in general functional capacity, grip strength and pinch strength (p < 0.001), and range of motion (p < 0.001; p < 0.005). After the treatment and after three months, all outcome measures showed statistically significant improvements. Conclusion rESWT is an effective method to decrease pain severity and improve general functional capacity, range of motion, grip strength, and pinch strength in patients with trigger finger. We concluded that the treatment of rESWT might be a non-invasive option to treat the trigger finger. However, randomized controlled trials are needed to provide more evidence of this treatment.