This chapter reviews the available international literature on the organizational antecedents of bullying and harassment by adopting the perspective of the work environment hypothesis as the main underlying theoretical explanation. According to this hypothesis, in a poorly organized work environment, employees experience high levels of stress and frustration, which may lead them to be involved in interpersonal conflicts, with some of these conflicts spiralling and evolving into bullying situations. Thus, the work environment hypothesis conceptualizes bullying as a behavioural strain outcome triggered by negative working conditions. Research adopting this explanation has grown considerably in the last decade or so, using progressively more convincing research designs. The chapter first presents a detailed description of the work environment hypothesis. It then reviews the main results of the first exploratory surveys on the role of working conditions in bullying that have consolidated such a hypothesis and have opened the way to more systematic and robust investigations. Next, it reports the evidence linking the following specific working conditions to bullying: job demands and job resources as conceptualized and measured according to two well-known job stress models (i.e. the demand–control–support model and the job demands–resources model); leadership characteristics; organizational change and job insecurity; organizational culture and climate; reward systems; and physical working conditions. In the concluding section, the main limitations of the available research will be highlighted and, based on these, directions for future research will be proposed.