Functional communication training, an intervention for challenging behavior rooted in principles of applied behavior analysis, has copious empirical support dating back to the mid-1980s for autistic individuals. Recently, there has been a concerted effort to thin reinforcement delivery during functional communication training using contingency-based delays that, in turn, are designed to enhance practicality and feasibility while not compromising on efficacy. In this synthesis, we meta-analyzed the literature using log response ratio effect sizes to investigate (a) combined and across type effectiveness of contingency-based delays and (b) moderating variables that might impact intervention outcomes. Findings showed that contingency-based delays were effective for autistic individuals (log response ratio = -2.17; 95% CI = (-2.76, -1.58)) and most effective when the contingency incorporated positive reinforcement (log response ratio = -2.30; 95% CI = (-2.83, -1.78)). In addition, delay procedures that included differential reinforcement of alternative behavior were overall more effective (log response ratio = -2.13; 95% CI = (-2.72, -1.55)) than those that involved differential reinforcement of other behavior (log response ratio = -1.24; 95% CI = (-3.84, 1.37)). Noteworthy moderating variables found to impact contingency-based delay efficacy included the intervention dosage and the topography of behavior. We discuss these findings and highlight directions where additional empirical research is warranted to improve our understanding about contingency-based delays for autistic individuals.