Title: Group actions on dimer models. Abstract: A dimer model is a bicolored graph on a 2-torus T with certain conditions. Although they were originally introduced as statistical mechanical models in the 60s, there has been discovered recently many relations of these models with other branches of mathematics and physics, in particular with several topics in Algebraic Geometry. In this talk I will explain some of their basic properties and constructions, introducing the notion of symmetric dimer model by the action of a finite group, which produces (non-commutative) crepant resolutions of non-toric non-quotient Gorenstein singularities in dimension 3. This is a joint work with Akira Ishii and Kazushi Ueda.