Most organizations develop social media policies in order to guide employees’ work-related social media behavior. Social media guidelines aim to minimize risks for the employer (e.g., criticism, cyberloafing) and maximize opportunities (e.g., brand ambassadorship). The past few years, both practice and research have become increasingly interested in social media guidelines. Research has predominantly looked for common themes within social media guidelines, how communication professionals view these guidelines and how guidelines can minimize legal liability for companies that dismiss employees due to their online behavior. Such research neglects the subject of the guidelines, however, and fails to take an employee-centric approach to examine social media in the workplace. For that reason, we first examine in depth what motivates employees’ social media behaviors (RQ1). Before we can understand how social media guidelines affect their behavior, we should first understand what drives employees to comment positively or negatively on their employer. Then, we can examine how social media guidelines should be drafted in order to minimize unwarranted social media behaviors among employees and maximize ambassadorship (RQ2). Besides an examination of the antecedents of social media behavior, the second part of our project is to examine its consequences. How do positive or negative messages from employees on social media affect the perception of an external audience and under what circumstances (RQ3)? To answer these questions we propose a combination of qualitative and quantitative research. The former allows us to explore employees’ motivations, attitudes and behavior in depth. The latter allows to examine the causal effects of social media guidelines and social media behavior.