Augmented Reality (AR) technologies open up new possibilities especially for task-focused domains such as assembly and maintenance. However, it can be noticed that there is still a lack of concepts and tools for a structured AR development process and an application specification above the code level. To address this problem we introduce SSIML/AR, a visual modeling language for the abstract specification of AR applications in general and AR user interfaces in particular. With SSIML/AR, three different aspects of AR user interfaces can be described: The user interface structure, the presentation of relevant information depending on the user’s current task and the integration of the user interface with other system components. Code skeletons can be generated automatically from SSIML/AR models. This enables the seamless transition from the design level to the implementation level. In addition, we sketch how SSIML/AR models can be integrated in an overall AR development process.