Public participation is a collective term for a variety of procedures aimed at involving stakeholders and ordinary people in decisions that may affect them. It is playing an increasingly important role in many democratic societies. Consequently, it has provided the impetus for a number of scientific studies. Most studies of public participation view the subject from a macro-level perspective; they focus on the criteria against which successful public involvement processes should be measured, the institutional arrangements and legal framework needed to achieve such success, etc. By contrast, relatively few studies have adopted a micro-level approach to public participation. Such an approach would entail concentrating on its psychosocial dynamics – in other words, on the behaviour and experience of individual participants, the relationships that form between individuals, the manner in which these shape deliberation and decision-making, etc. The aim of this study was therefore to address the aforementioned imbalance. It took the form of an integrative literature review encompassing publications in the fields of psychology and public participation. Its objectives were (a) to develop a theory of the psychosocial dynamics of public participation; (b) on the basis of this theory, to identify ways in which the effectiveness of public involvement processes might be enhanced; and (c) to propose avenues for future research in the field. Systems theory was chosen as a meta-theoretical framework to guide the process of theory-building. Systems theory may be defined as the study of interrelationships between the properties of whole systems and the properties and organisation of their component elements. Hence, it provided a means of demonstrating how the micro-level aspects of a public participation process (such as the actions, motives and perceptions of individual participants) interact with macro-level variables (such as the cultural and socio-political milieu in which it is embedded) to shape its course and outcomes. On the basis of the study, five complementary models of public participation were constructed. The first three models depict the macro-level characteristics of public participation. These set the stage for the remaining two models, which encompass both its macro- and micro-level dynamics.