Groups incur a number of internal costs when members work in different geographic locations and represent different functional areas. For example, it can be difficult for distributed group members to develop a common understanding of the task, or for cross-functional group members to reconcile dissimilar points of view. Relatively little scholarly attention, however, has been given to the external benefits that distributed or cross-functional group members have available to them. These include access to diverse sources of knowledge, such as customers in a variety of locations or non-group employees from different functions. Past studies have shown a positive relationship between external knowledge sharing and work group performance. This paper extends previous research by examining whether distributed or cross-functional groups benefit from external knowledge sharing more than co-located or functionally homogeneous groups. I surveyed 182 work groups in a Fortune 500 corporation to assess how often members shared general overviews, specific requirements, analytical techniques, progress reports, and project results within and outside of the group. Members were located around the world, they represented numerous functional areas, and they worked on tasks ranging from product development to manufacturing operations. Senior managers in the company rated each work group on their performance. I hypothesized and found that both internal and external knowledge sharing were positively related to group performance. Building on social network theory, I also hypothesized and found that as geographic distribution and cross-functionality increased, the relationship between external knowledge sharing and group performance became even stronger.These results suggest that external networks can provide distributed or cross-functional group members with access to unique task information, know-how, and feedback.3