The mechanical behavior of 2D materials is governed by an extremely low bending rigidity and high in plane stiffness and strength. This unique combination makes these materials appealing for fundamental research as the thinnest membranes ever known but also in applications where flexibility and strength are desirable. In this talk I will give an overview of the mechanical properties of 2D materials to provide a framework to our recent studies on mechanical response of graphene and MoS2 with controllably induced atomic defects.