Recent research into the mental health of PhD candidates suggests that their high levels of stress could be caused in part or exacerbated by aspects of the doctoral education environment. However, the particulars of this environment have not been explored in consistent enough ways to provide a clear way forward for universities to respond to this issue. This article presents a systematic scoping review of the recent literature on this topic with the aims of collecting and consolidating the heterogeneous range of findings therein and providing a framework to coordinate further research and inform intervention design. Factors shown by the literature to contribute to stress in doctoral settings are presented, including problems in the supervisory relationship, lack of transparency of university processes, workload, role conflict, financial insecurity and uncertain career prospects. Analysis of the review sample indicates four main themes in this body of literature: shifting ideas about the range of environmental stressors and the relationships between them, a paucity of trialled interventions that target the range of known stressors, a lack of standardisation in instruments used for capturing the effects of stressors and evaluating interventions and finally, a need for comprehensive, agreed upon typologies -- to integrate what is known about the issue and prioritise interventions. This article proposes guidelines to address these deficiencies, based on an ecological understanding of the doctoral research setting.