A User Interface Description Language (UIDL) is a formal language used in Human-Computer Interaction (HCI) in order to describe a particular user interface independently of any implementation. Considerable research effort has been devoted to defining various meta-models in order to define rigorously the semantics of a UIDL. These meta-models adhere to the principle of separation of concerns. Any aspect of concern should univocally fall into one of the following meta-models: context of use (user, platform, environment), task, domain, abstract user interface, concrete user interface, usability (including accessibility), workflow, organization, evolution, program, transformation, and mapping. Not all these meta-models should be used concurrently, but may be manipulated during different steps of a user interface development method. In order to support this kind of development method, software is required throughout the user interface development life cycle in order to create, edit, check models that are compliant with these meta-models and to produce user interfaces out of these methods. This workshop is aimed at reviewing the state of the art of software support for a UIDL in the context of any development method (e.g., formal method, model-based, model-driven). From this review, a taxonomy of software support for UIDLs will emerge that will serve for describing, comparing, and exploring software support for UIDLs.