Burnout among radiologists is increasingly prevalent, with the potential for having a substantial negative impact on physician well-being, delivery of care, and health outcomes. To evaluate this phenomenon using reliable and accurate means, validated quantitative instruments are essential. Variation in measurement can contribute to wide-ranging findings. This article evaluates radiologist burnout rates globally and dimensions of burnout as reported using different validated instruments; it also provides guidance on best practices to characterize burnout. Fifty-seven studies published between 1990 and 2023 were included in a systematic review, and 43 studies were included in a meta-analysis of burnout prevalence using random-effects models. The reported burnout prevalence ranged from 5% to 85%. With the Maslach Burnout Inventory (MBI), burnout prevalence varied significantly depending on the instrument version used. Among MBI subcategories, the pooled prevalence of emotional exhaustion was 54% (95% CI, 45-63%), depersonalization was 52% (95% CI, 41-63%), and low personal accomplishment was 36% (95% CI, 27-47%). Other validated burnout instruments showed less heterogeneous results; studies using the Stanford Professional Fulfillment Index yielded a burnout prevalence of 39% (95% CI, 34-45%), whereas the validated single-item instrument yielded a burnout prevalence of 34% (95% CI, 29-39%). Standardized instruments for assessing prevalence alongside multidimensional profiles capturing experiences may better characterize radiologist burnout, including change occurring over time.