Employee ideation on internal social media (ISM) is a new way of communicating about ideas among employees, and is being adopted more and more, particularly in large organizations. Thus, all employees in an organization may be invited to suggest and develop innovative ideas on ISM, as all employees are regarded as valuable internal innovation sources. However, and although ISM is assumed to facilitate idea sharing and collaboration among employees, employee ideation on ISM often suffers from low employee participation. This dissertation suggests that ideation is communication. Hence, communication constitutes an important dimension of employee ideation on ISM, but it has only attracted little attention in the research literature of online employee ideation. Therefore, the purpose of the dissertation is to empirically explore and enhance the understanding of employee ideation on ISM from a managerial, a dialogue and an employee perspective in order to create insights into the dynamics of employee ideation on ISM from a communicative perspective.In order to fulfill the overall research purpose three sub-questions were asked, namely 1) what do managers expect of employee ideation on ISM, and what do they perceive as contributions of and/or barriers to employee ideation on ISM?, 2) how do employees through dialogue strategies address uncertainty in order to generate ideas on ISM? and 3) what enables and what acts as barriers to meaningfulness, safety and availability in relation to employee engagement in ideation on ISM?The dissertation builds on a social-constructivist approach and is framed within the strategic communication perspective inspired by the Communicative Constitution of Organization (CCO) approach. The theoretical framework of this dissertation draws on research literature from open innovation (Chesbrough, 2003), employee ideation on ISM (Beretta et al., 2018; Rozaidi et al., 2017; Stieger et al., 2012; van den Ende et al., 2015), internal innovation communication (Patsch & Zerfass, 2013; Pfeffermann, 2017; Zerfass, 2005; Zerfass & Huck, 2007), and coworker communication (Heide & Simonsson, 2011) in order to shed light on employee ideation on ISM from a communication perspective. Moreover, four sets of theories have been applied in this dissertation. They are theories related to ISM affordances (Faraj & Azad, 2012; Leonardi & Vaast, 2017; Robey, Raymond & Anderson, 2012; Treem & Leonardi, 2012), uncertainty (Raupp, 2018; Weick, 2001), imagined dialogues (Bakhtin, 1984; Shotter, 2008) and the psychological engagement conditions (Kahn, 1990).The empirical material is based on two qualitative studies. The first study is an explorative study conducted with ten large and knowledge-intensive organizations across different industries in Denmark. The second study is a single case study conducted in one large knowledge-intensive Danish organization (organization C). The three articles of the dissertation are based on the findings from the two studies each representing the three different perspectives on employee ideation on ISM.The first article “Employee ideation on internal social media: Balancing managerial expectations” embraces the managerial perspective, and its purpose is to explore managers’ expectations of employee ideation on ISM and their perceptions of the contributions and barriers of this new way of generating ideas online. Managers responsible for employee ideation on ISM from ten large and knowledge-intensive organizations across different industries were interviewed. It was found that not only managers’ overly optimistic but also overly pessimistic expectations to employee ideation on ISM may hinder managers in unravelling barriers for employee ideation on ISM to prosper because of either disregarding critical signals due to the optimistic expectations or enacting an environment which confirms the low expectations. The article suggests that the managerial expectations become more balanced as managers responsible for employee ideation on ISM become aware of their important communication role in employee ideation and start to act as communication facilitators and sense-givers in the online ideation process.The second article “Employee Ideation on Internal Social Media: Addressing Uncertainty Through Dialogue Strategies” explores from a dialogue perspective how employees through dialogue strategies address uncertainty when they generate ideas on ISM. In order to create deeper insights into and understanding of how multi-vocal dialogues about ideas on ISM unfold in a context of uncertainty, online observations of employee communication about ideas were conducted in organization C. One ideation session of 70 ideas, including 263 comments, and 340 likes was selected for a more detailed analysis of employee communication when generating ideas on internal social media. The study found that employees addressed uncertainty through seven dialogue strategies to mitigate communication imagined to be face threatening. The article concludes that uncertainty and dialogue strategies are resources for online employee ideation. Uncertainty may offer the opportunity for open, reflective and stimulating dialogues, and the dialogue strategies may enhance online ideation.The third article “Employee engagement in generating ideas on internal social media: A matter of meaningfulness, safety and availability” covers the employee perspective, and it explores employees’ perceptions of enablers and barriers to engage in multi-vocal dialogues about ideas on ISM. Based on online observations of the employee ideation and on semi-structured interviews with 14 employees and two managers in organization C, the study identified various enablers and barriers to engagement related to psychological meaningfulness, safety and availability. In particular, employees’ perceptions of management innovation communication, peer communication, ISM affordances and of feeling an opportunity for contributing to innovation were found to be significant enablers or barriers of employee engagement. Furthermore, the study identified specific tensions when employees engage in generating ideas on ISM such as obligation vs. option to ideate and employee influence vs. no influence, which may constitute further barriers for employees to engage in online ideation. The article suggests that acknowledging communication reciprocity in employee ideation on ISM is key in enabling employee engagement, and that not only employees, but also managers, are dialogue partners in employee ideation on ISM.Based on the findings of the two qualitative studies, the insights created into the dynamics of employee ideation on ISM from a communication perspective have been found to be related to four themes. These themes have been centered on 1) the balancing of managers’ and employees’ expectations of employee ideation on ISM, 2) employees are active communicators in internal innovation communication, 3) managers are dialogue partners and 4) ISM is an arena for the construction of ideas through multi-vocal dialogues. The overall contribution of the dissertation is the theoretical framework and its contribution to the research field of strategic communication. The study is one of the first to explore employee ideation on ISM from a communicative perspective, and it has developed the strategic communication research area in terms of focusing on the micro-level processes of middle manager and employee communication in relation to ideation on ISM. For theory, this implies at least three propositions. First, the dissertation suggests extending the understanding of internal innovation communication to also embrace the employee perspective. Next, it is suggested that communication reciprocity both among employees and among managers and employees is understood as key to enabling the multi-vocal dialogues about ideas on ISM and employee engagement. The third implication for theory is an understanding of ISM as an arena for the construction of ideas through multi-vocal dialogues. Main implications for practice at a managerial level are that managers acknowledge their important role as dialogue partners in employee ideation on ISM and that they learn or enhance their communicative leadership skills in relation to employee ideation on ISM. Consequently, they can strategically use dialogues to embrace listening and response in order to foster employee engagement and participation in online ideation. At an employee level, the main implication is that employees embrace a dialogic orientation when they generate ideas. With a dialogic orientation, employees are likely to apply dialogue strategies to address the inherent uncertainties of employee ideation on ISM and to foster open, reflective and stimulating multi-vocal dialogues about ideas on ISM and thereby ultimately increase the potentials for constructing ideas on ISM.