Background and Aims: The construct of mathematics anxiety has received increasing attention in the past decades because of its correlation with mathematics performances, achievements, and subsequent choice of STEM majors and careers. Intervention research and reviews on the topic have been directed predominantly to school-age students, while little is known about interventions for (young) adults, and quantitative reviews are missing. Methods: The present study aims to conduct a meta-analytic review of interventions on mathematics anxiety levels in (young) adults. Searches were conducted using the following databases: ERIC, MEDLINE, PsycINFO, SAGE, Scopus, and Web of Science. Twelve studies published in English language from the year 2000 were included in this meta-analysis. The selected studies included mathematics anxiety interventions targeted at the population aged 18 and older. Interventions ranged from one-time sessions to six months programs and were integrated into a mathematics course. The studies compared intervention effectiveness with a control condition and tested the efficacy of relaxation techniques, clinical psychological interventions, focused mathematics skills training, and improved teaching practices. The quality of the included articles was assessed, and the quantitative statistics were computed (using RevMan and the metafor package of R) under the Random Effect Model assumption. Results: The meta-analysis showed 1) a small-to-medium, significant overall intervention effect (d = −0.31, 95% CI [-0.44, -0.19], p < 0.001), 2) a null variability of true effect sizes (τ2 = 0), and 3) consistency (negligible heterogeneity) across studies (I2 = 4%, p=0.41). Potential sources of bias that may have lowered the precision of the study are discussed. Conclusions: This work supports the introduction of mathematics anxiety intervention in classroom practice for (young) adults. The findings are discussed in the context of other evidence and point to future research directions.