Including stakeholder perspectives in environmental decision making is in many countries a legal requirement and is widely seen as beneficial as it can help increase decision legitimacy, likelihood of implementation, and quality of the outcome. Whereas the theoretical literature on stakeholder engagement is large, less attention has been devoted to comparing and discussing different methodological approaches. Here, we compare three approaches—multi-criteria analysis, plural rationality theory, and scenario construction—that include stakeholders’ perspectives in environmental decision making. We find differences between the approaches concerning the assumptions about stakeholder rationality and whether experts and/or stakeholders are in charge of framing the problem. Further differences concern the type of data input from stakeholders and how it is used by the experts, as well as the role of stakeholders and whether they are involved early—already for identifying options—or later in the process, for evaluating or ranking alternatives analyzed by the experts. The choice of approach thus predetermines the type and depth of stakeholder engagement. No approach is “better” than another, but they are suited for different problems and research aims: the choice of the approach, however, has a large impact on the results.