Participation is central to the organization of social interaction, in particular for shaping the contributions of diverse parties to the ongoing activity as well as the options they have to contribute to it. This chapter discusses different ways in which the notion of participation is used in conversation analysis (CA), and how it addresses a diversity of conceptual and analytical issues. This chapter first presents some conceptual issues and then discusses methodological challenges raised by the documentation of participation in video recordings and transcriptions. Next, it elaborates on how participation relates to key phenomena in multimodal CA, such as turn-taking, interactional space, haptic sociality, and multi-activity, relying both on the literature and on empirical illustrations. In conclusion, some future directions for research on participation are outlined.