Work teams must increasingly operate in complex environments characterized by multiple external actors beyond team and organizational boundaries. Although previous research demonstrates the importance of boundary spanning activities to team effectiveness, it reveals relatively little about the process of boundary spanning in these environments. In this article, we investigated the processes of boundary spanning across multiple external actors in 10 cross-organizational teams. We identified three sequences for reaching out to external actors: (a) moving inside-out from vertical actors inside the host organization to horizontal actors outside of the host organization, (b) moving outside-in from horizontal actors to vertical, and (c) staying-inside with vertical actors from the host organization. Our observations suggest that inside-out and outside-in sequences were more successful than simply pleasing the host organization. We build on our empirical findings to develop a process theory of how team boundary spanning activities across multiple external actors influence team effectiveness. Our research underscores the importance of a team’s interactions with actors in its external environment beyond those in an immediate supervisory role and provides insight into the dynamics of boundary spanning in multi-organizational contexts.