As employees increasingly interact with their professional contacts on online social networks that are personal in nature, such as Facebook or Twitter, they are likely to experience a collision of their professional and personal identities that is unique to this new and expanding social space. In particular, online social networks present employees with boundary management and identity negotiation opportunities and challenges, because they invite non-tailored self-disclosure to broad audiences, while offering few of the physical and social cues that normally guide social interactions. How and why do employees manage the boundaries between their professional and personal identities in online social networks, and how do these behaviors impact the way they are regarded by professional contacts? We build a framework to theorize about how work-nonwork boundary preferences and self-evaluation motives drive the adoption of four archetypical sets of online boundary management behaviors (open, audience, content, and hybrid), and the consequences of these behaviors for respect and liking in professional relationships.