Primary evidence-based treatment approaches for ADHD involve pharmacological and behavioral treatments. However, there continue to be investigations of cognitive-behavioral, cognitive, and neural-based intervention approaches that are not considered evidence-based practice. These particular treatments are summarized, as they all involve training in cognitive skills or cognitive strategies. We identified 26 studies (six cognitive-behavioral, six cognitive, and 14 neural-based), and calculated effect sizes where appropriate. Overall, our analysis suggests that further research is needed to determine the efficacy of these approaches on both cognitive and behavioral outcome measures, but that some of these methods show promise for treating ADHD. We discuss some important conceptual and methodological issues that need to be taken into account for future research in order to evaluate the clinical efficacy of these approaches.