Chelation treatment is used to eliminate specific metals from the body, such as mercury. It has been hypothesized that mercury poisoning may be a factor in autism and data suggest that perhaps 7% of individuals with autism spectrum disorder (ASD) have received chelation treatment. It would therefore seem timely to review studies investigating the effects of chelation treatment for individuals with ASD. To this end, we conducted a systematic search to identify studies that have evaluated the effects of chelation on autism symptomatology. Our search identified five studies, which were analyzed in terms of (a) participant characteristics, (b) dependent variables, (c) study outcomes, and (d) certainty of evidence. Four of the five studies found mixed results and only one study reported positive results. However, given the significant methodological limitations of these studies, the research reviewed here does not support the use of chelation as a treatment for ASD. (Contains 1 table.)