Over the past few decades, the widespread use of mobile work devices (MWDs: e.g., laptops and smartphones) has enabled constant connectivity to work. This study advances previous work on the effects of constant connectivity for employees by focusing on how and for whom constant connectivity might be related to employee well-being. Additionally, organizational-level antecedents of constant connectivity are investigated. This paper reports on two survey studies that a) operationalize constant connectivity and its organizational antecedents and b) investigate the relationship between constant connectivity and employee well-being. The findings demonstrate that constant connectivity is negatively related to employees' well-being due to the inability to disengage from work. Moreover, this negative association exists independently of employees' boundary preferences. The findings further suggest that perceived alignment between perceived functional, physical, and symbolic connectivity aspects of MWDs and occupational identity, susceptibility to social pressure, and the visibility of co-workers' communication practices all contribute to constant connectivity in the workplace. Due to the use of mobile work devices (MWDs), employees can be constantly connected to their colleagues and clients (Perlow, 2012). Constant connectivity has been described as intrinsic to contemporary knowledge work (