This paper extends Li (2008b) to the multi-agent environment, where players reason about each other’s awareness as well as knowledge, subject to their own awareness constraints. I characterize the interactive knowledge hierarchies under unawareness, which significantly differ from those in the standard information partition model by allowing for false interactive knowledge. Aumann’s classic characterization of common knowledge does not immediately apply in this environment, even if there is “common awareness” of the event involved. An alternative characterization of common knowledge is provided.