The ability to reason about relations is relevant for many spa-tial cognitive processes. This can involve: (i) to represent spa-tial information mentally, (ii) to manipulate the spatial repre-sentation, and (iii) to infer new spatial information. Severalcognitive theories make assumptions and predictions about theunderlying processes. A detailed and systematic overview andanalysis of ireliable effects across studies is missing. This ar-ticle presents a meta-analysis of 35 studies about spatial rela-tional reasoning. Studies were classified according to differentfactors including the ambiguity of the spatial description, i.e.,if it the description allows for more than one representation, thepresentation of information, i.e., if the information has beenpresented auditorily or in a written form, and the task, i.e., ifa conclusion or model of the premises needs to be generatedor verified. Implications of the findings for the mental modeltheory and working memory are discussed.