Editorial board positions are prestigious and have important implications as gatekeepers for the advancement of academic surgeons. We assessed the composition of editorial boards of cardiothoracic surgery journals to identify female and low- and middle-income country (LMIC) representation. Journals listed as "Cardiac and Cardiovascular Systems" in the 2019 InCites Journal Citation Reports (JCR) directory by Clarivate Analytics were manually searched to identify journals pertaining to cardiothoracic surgery. Editorial boards for each journal were reviewed as available on journal websites, assessing for sex and country income group (high-income country vs. LMIC) of editorial board members. Descriptive statistics were performed, and differences were assessed through t tests and correlations using STATA version 14. Twenty-two cardiothoracic journals were identified, of which 16 were listed on JCR and 6 were sister journals. A total of 1,970 editorial board members were identified, of whom 206 (10.5%) were female and 103 (5.2%) from LMICs (each, p < 0.001). Female representation varied between 0% and 29.7% across journals. There were 391 associate and deputy editors, 62 (15.9%) were female and 15 (3.8%) from LMICs (each, p < 0.001). Only 1 (4.5%) of the 22 journals had a female Editor-in-Chief. A total of 15 LMICs were represented: Brazil (56 members), China (11 members), and India (11 members). LMIC representation varied between 0% and 76.6% (Brazilian Journal of Cardiovascular Surgery), with the second highest representation being only 16.33%. After excluding the Brazilian Journal of Cardiovascular Surgery (the only country-specific journal), LMIC representation was only 3.7% on editorial boards. The intersection between female sex and LMIC origin was found in only three editorial board members. A statistically significant positive correlation was seen between percentage of females in editorial boards and journal impact factor (r= 0.769, p < 0.001). No correlation was seen between percentage of LMIC in boards and impact factor (r = -0.306, p = 0.250). Our findings suggest editorial boards of cardiothoracic surgery journals remain highly imbalanced in terms of sex and country income group. Disparities in editorial boards may further result in less inclusive review processes, which may lead to fewer publications and slower academic advancement by underrepresented groups. Societies should partake in active assessment and reporting of disparities across their editorial boards as well as assessment of implicit biases and barriers impeding female and LMIC researchers from joining their boards.