Outsourced information systems development projects are especially complex, as they cross both external (client-vendor) and internal boundaries (among stakeholder groups within the client organization). We propose a boundary spanning theoretical lens to assess the quality of external and internal communication among involved groups and suggest that the quality and extent of boundary spanning have an impact on the success of an outsourcing relationship and the project’s outcomes. This paper reports on the development and testing of constructs which are part of a survey instrument assessing the extent and quality of boundary spanning in a client organization. Construct validation is based on responses from 197 project managers. The constructs will be used to test a model of internal and external boundary spanning activity in outsourced IS development. Uncovering the implications of client boundary spanning practices for outsourcing relationship management will be of significant value for researchers and for practicing project managers.