This dissertation examines leaders' experiences of work stress, using distinct methods, perspectives, and groups of leaders. Guided by conservation of resources and stressor-strain theories, I focus on prevalent workplace stressors, the processes through which leaders are impacted, and ways organizations can mitigate negative outcomes for leaders. Study 1 examined effects of mistreatment on leaders in a Canadian manufacturing firm, among 86 leader-direct report dyads. Results from surveys collecting quantitative data and soliciting open-ended comments indicated that leaders' experiences of workplace incivility are related to their own subsequent reports of disengagement, job dissatisfaction, and turnover intentions, as well as follower reports of the same outcomes, all through increased leader burnout. Taking a follower perspective to enhance the understanding of employees' perpetration of mistreatment directed at leaders, Study 2 examined the effects of COVID-19-related grief on leader-directed deviant behaviours among young workers during the COVID-19 pandemic. Results from Participant Group 1 (N = 98; 1st wave) suggested young adults experiencing COVID-19-related grief engaged in more leader- and organization-directed deviant behaviours, through the mediating effect of role overload. Results from Participant Group 2 (N = 760; 2nd wave) supported and extended the findings from Participant Group 1, by demonstrating that perceived organizational support moderated the negative effects of role overload on deviant behaviours. Finally, Study 3 examined the effects of work-family conflict and COVID-19-related grief on 334 North American leaders. Mediation analyses suggested work-family conflict and COVID-19-related grief are negatively associated with work (i.e., laissez-faire behaviours and turnover intentions) and personal (i.e., family cohesion and well-being) outcomes, through role overload and burnout. Organizational support of work-life balance moderated these effects. Although employee outcomes have been widely studied in the leadership literature, leader outcomes have been largely excluded. Moreover, despite the habitually stressful nature of work for leaders, little research has focused on understanding work stress for this cohort of the workforce. This dissertation addresses these gaps in the literature. Taken together, results from these three studies indicate many ways in which work stressors influence leaders, and the important role of organizations in determining any negative outcomes.