In the field of sustainability, scholars, and policy-makers herald the transformative power of participation in knowledge production. However, a discrepancy between these expectations and the limited understanding of the complex interactions constituting participation processes can be observed. With the aim of critically analysing these complex interactions, this paper develops a conceptual perspective on participation as a relational space which is formed in the interplay of structures and processes. This perspective is applied to the analysis of empirical literature in sustainability research, development research, and science and technology studies. The literature review guided by the proposed conceptualisation systematically draws together the rich experience with participation in knowledge production. Elements constituting participation spaces along the dimensions `structures' and `actors' are identified and discussed in relation to `processes' of space-making: (i) (in)coherences with reference system, (ii) resources, (iii) timing, (iv) expectations, (v) mutual trust, and (vi) worldviews and values. Power relations are found to pervade the three dimensions. Enhanced conceptual-analytical clarity of the elements constituting participation spaces provides a differentiated basis for discussing the transformative power of participatory knowledge production. By stimulating reflexivity on the making of participation, this approach contributes to better understanding when spaces of participation have the capacity to become spaces of transformation.