Electroconvulsive therapy (ECT) is one of the most effective treatments for mood disorders, but patients and the general public often have negative perceptions and inaccurate knowledge about ECT. A systematic review of measures assessing perceptions and knowledge about ECT was conducted, including all published peer-reviewed journal articles from 1938 to 2018. Inclusion criteria were studies that included psychiatric patient samples and reported quantitative measures assessing perceptions and/or knowledge related to ECT. An initial 112 articles identified were distilled to 31 studies that were ultimately selected for inclusion in the review. Selected studies spanned 15 countries across 5 decades and included 570 individual measurement items. Items were categorized into 8 content domains under 2 overarching concepts of perceptions (97% of studies) and knowledge (77% of studies). Among gaps in content domains, the role of health-care providers in ECT within perceptions domains was rarely assessed by existing measures. And among knowledge domains, the scientific evidence for ECT was least assessed by existing measures. Among all studies reviewed, only 3 studies reported the psychometric properties of the measures used. Together, these findings demonstrate that a variety of measures have been used to assess a range of psychosocial domains related to ECT. However, not one measure comprehensively examined all domains and reported psychometric properties. Thus, there is great potential for new measures to be developed both for research and as patient education tools for ECT treatment. (PsycInfo Database Record (c) 2021 APA, all rights reserved).