•Evidence on the anxiolytic effects of exercise in anxiety and related disorders has grown in recent years.•Exercise has a small effect on reducing anxiety symptoms in anxiety and related disorders.•Although the current meta-analytic evidence has less statistical heterogeneity than previously reported, future research still needs to elucidate the moderate levels of heterogeneity in detail. Exercise as a treatment option for people with mental disorders is a field of growing interest. The increased number of published randomized controlled trials (RCTs) evaluating the effects of exercise in the treatment of anxiety and related disorders in recent years calls for an update of the available meta-analytic evidence. Electronic databases (PubMed, CINAHL, PSYCArticles, and Embase) were searched up to 17.2.2021, for RCTs evaluating the effects of exercise on anxiety and stress symptoms in adults with anxiety and related disorders. A random effects meta-analysis was conducted. A total of 13 RCTs comprising 731 adult participants (exercise n=376; control n=355) were included. Exercise had a small, bordering medium, but statistically significant effect on decreasing anxiety symptoms compared to control condition (standardized mean difference=-0.425, 95%CI -0.67 to -0.17; I2 = 47.9%) in people with anxiety and related disorders. Our meta-analysis updates the existing evidence supporting exercise as an efficacious intervention for anxiety and related disorders. Although the updated meta-analytic evidence is less heterogenous than previously reported, future research is still needed to explore the factors moderating the effects of exercise on outcome such as frequency, intensity, duration of the sessions, and type of exercise and qualification of the provider in more detail.