An electric motor may include a stator assembly comprising a stator housing, and one or more rotors coupled to the stator by a rotor shaft assembly. The stator housing may include a cooling structure that has a plurality of cooling body portions and a plurality of cooling conduits defined by the plurality of cooling body portions. A method of forming a stator housing for an electric machine may include additively manufacturing a stator housing that includes a cooling structure defining a fluid domain, coupling a working fluid source to the stator housing and introducing a working fluid into the fluid domain defined by the cooling structure, and sealing the cooling structure with the working fluid contained within the fluid domain of the cooling structure. A method of cooling an electric machine may include heating the working fluid in the fluid domain and flowing the working fluid through the fluid domain, and transferring heat from the cooling structure to a cooling fluid flowing along one or more cooling surfaces contacting a surface of the electric machine.