High rates of nonresponse to evidence-based treatment for posttraumatic stress disorder (PTSD) have fueled the search for improved intervention. Evidence suggests that improvements in dispositional mindfulness (i.e., tendency to attend to the present with nonjudgment and nonreactivity) may help reduce PTSD symptoms. While some research suggests that transdiagnostic mindfulness-based interventions particularly target avoidance symptoms, the association between dispositional mindfulness and avoidance has yet to be systematically examined. To address this gap, we examined peer-reviewed studies that reported quantitative associations between avoidance and dispositional mindfulness among trauma-exposed adults, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 guidelines. Sixteen studies were identified for final review from PsycINFO and PubMed databases. Results suggest that mindfulness has a weak relationship with effortful avoidance. This weak relationship may be obscured in studies where effortful avoidance is measured among other symptoms (e.g., anhedonia). Mindfulness appeared to have stronger associations with symptoms of hyperarousal and negative alterations in cognition and mood. An important clinical implication is that high effortful avoidance may manifest among patients who report strong mindfulness skills. It may be helpful for clinicians to carefully assess how mindfulness is being used to cope.