The group literature has been paid most attention to the basic question of formation, with post-formation issues captured by the broad term of ''group maintenance''. By contrast the literature is remarkably silent on the question of the ''organizational form'' in which groups form or survive. This relative silence on ''form'' – and changes in ''form'' over time – might be read to imply that the precise way groups are put together organizationally is of little consequence. But this is far from the case; with form being linked to a range of group capacities, not least the provision of meaningful democratic participation and the ability to support state policy implementation. Taking this point of departure, this paper contends that groups scholarship might profit from a more focused debate about the tools or frameworks that could guide such as style of empirical and analytical work. Building on recent work moving in this direction, the aim of this paper is to encourage debate by exploring ways we might use concepts like ‘organisational form’ to get a handle on the dynamic of group evolution. The paper also presents a framework for describing organisational form, and levels of change in group form. This discussion is supported by illustrative examples from predominantly UK group cases.