Background Carotid structural changes measured by intima media thickness (IMT) have been related to cognitive complaints during aging. Therefore, the aims of this meta-analysis were (1) to elucidate the relationship between vascular status, measured as IMT, and cognitive domains distinguishing between global cognition, executive functions, memory and attention; and (2) to explore whether demographic (ie, age and sex), clinical (ie, body mass index and IMT baseline values), and procedure characteristics influence this association. Methods and Results We performed a systematic review of MEDLINE (via PubMed), Scopus, and Web of Science databases from their inception to June 2021. Studies meeting the following inclusion criteria were included: (1) the participants were adults; (2) the exposure was carotid IMT; (3) the outcome was cognitive function, including global cognition, executive function, memory, and attention measured using standardized tests; and (4) the study design was cross-sectional or longitudinal including unadjusted and adjusted analyses. A total of 19 cross-sectional and 15 longitudinal studies were included and demographic (age and sex), clinical (body mass index and baseline IMT values), and procedure characteristics were analyzed as potential mediator or moderators of the association. Conclusions Our data support negative associations between IMT and cognitive function in cross-sectional studies. The association between IMT and cognition lost significance in longitudinal studies and when controlling for covariates in cross-sectional studies. Finally, the strength of these associations seems not to be modified by age, sex, body mass index, and baseline IMT values. This systematic review and meta-analysis adds to the evidence supporting the use of IMT as a measure for identifying patients at risk of cognitive decline.