Comparative thinking is ubiquitous in human cognition. Empirical evidence is accumulating that PTSD symptomatology is linked to various changes in social, temporal and counterfactual comparative thinking. However, no systematic review and meta-analysis in this line of research have been conducted to this date. We searched titles, abstracts and subject terms of electronic records in PsycInfo and Medline from inception to January 2019 with various search terms for social, temporal and counterfactual comparative thinking as well as PTSD. Journal articles were included if they reported a quantitative association between PTSD and social, temporal and/or counterfactual comparative thinking in trauma-exposed clinical or sub-clinical samples. A total of 36 publications were included in the qualitative synthesis. The number of publications on the association between PTSD and social and temporal comparative thinking was too scarce to warrant a meta-analytic review. A narrative review of available literature suggests that PTSD is associated with distortions in social and temporal comparative thinking. A meta-analysis of 24 independent samples (n = 4423) assessing the association between PTSD and the frequency of counterfactual comparative thinking yielded a medium to large positive association of r =.464 (p <.001, 95% CI =.404; .520). Higher study quality was associated with higher magnitude of association in a metaregression. Most studies collected data cross-sectionally, precluding conclusions regarding causality. Overall, study quality was found to be moderate. More longitudinal and experimental research with validated comparative thinking measures in clinical samples is needed to acquire a more sophisticated understanding of the role of comparative cognitions in the aetiology and maintenance of PTSD. Comparative thinking might be a fruitful avenue for a better understanding of posttraumatic reactions and improving treatment.