The role of need for cognitive closure (NFCC) in reasoning about social relations was investigated. Participants learned pairwise liking/disliking relations between people who could also be categorised on the basis of nationality and then had to group them into social cliques. The social clique structures were either consistent or inconsistent with the nationality categorisation, and the diagnostic information that was necessary to determine the number of cliques appeared either early or late in the information sequence. We expected participants under conditions of high (vs low) NFCC to rely more on heuristic processing. As predicted, high (vs low) NFCC participants were less accurate in their representations of cliques when the clique structure was inconsistent with the nationality category (Study 1 and 2) and when the diagnostic information was presented late (Study 1). The implications regarding the influence of NFCC on reasoning and the role of specific NFCC manipulations are discussed.