Enterprise architecture (EA) is a coherent whole of principles, methods, and models that are used in the design and realization of an enterprise’s organizational structure, business processes, information systems, and IT infrastructure. EA is used as a holistic approach to keep things aligned in a company. Some emphasize the use of EA to align IT with the business, others see it broader and use it to also keep the processes aligned with the strategy. Recent research indicates the need for EA in small and medium-sized enterprises (SMEs), important drivers of the economy, as they struggle with problems related to a lack of structure and overview of their business. However, existing EA frameworks are perceived as too complex and, to date, none of the EA approaches are sufficiently adapted to the SME context. Therefore, in this PhD, we present the CHOOSE approach for EA for SMEs. The approach consists of four artifacts: a metamodel, a method, software tool support, and a visualization. The approach is kept simple so that it may be applied in an SME context and is based on the essential dimensions of EA frameworks. Five steps were taken: first, the problem of EA in SMEs was extensively analyzed. Next, the CHOOSE metamodel was developed during action research in SMEs. Then, action research in six companies was used to develop an adequate method (consisting of guidelines, a roadmap, and stop criteria) and to further refine this CHOOSE metamodel, while different types of software tools (PC, iPad, Android, ...) were developed to enable the evaluation rounds. Finally, a proper visualization was established.