BACKGROUND: Military veterans report high rates of psychiatric and physical health symptoms that may be amenable to mindfulness-based interventions (MBIs). Inconsistent prior findings and questions of fit between MBIs and military culture highlight the need for a systematic evaluation of this literature. OBJECTIVE: To quantify the efficacy and acceptability of MBIs for military veterans. DATA SOURCES: We searched five databases (MEDLINE/PubMed, CINAHL, Scopus, Web of Science, PsycINFO) from inception to October 16th, 2019. STUDY SELECTION: Randomized controlled trials (RCTs) testing MBIs in military veterans. RESULTS: Twenty studies (k = 16 unique comparisons, N = 898) were included. At post-treatment, MBIs were superior to non-specific controls (e.g., waitlist, attentional placebos) on measures of posttraumatic stress disorder (PTSD), depression, general psychological symptoms (i.e., aggregated across symptom domains), quality of life / functioning, and mindfulness (Hedges' gs = 0.32 to 0.80), but not physical health. At follow-up (mean length = 3.19 months), MBIs continued to outperform non-specific controls on general psychological symptoms, but not PTSD. MBIs were superior to specific active controls (i.e., other therapies) at post-treatment on measures of PTSD and general psychological symptoms (gs = 0.19 to 0.25). Participants randomized to MBIs showed higher rates of attrition than those randomized to control interventions (odds ratio = 1.98). Several models were not robust to tests of publication bias. Study quality and risk of bias assessment indicated several areas of concern. CONCLUSIONS: MBIs may improve psychological symptoms and quality of life / functioning in veterans. Questionable acceptability and few high-quality studies support the need for rigorous RCTs, potentially adapted to veterans.