Research-practice partnerships (RPPs) offer a strategy for supporting educational change and bringing researchers and practitioners into meaningful engagement around pressing issues. Whereas traditional research models often position researchers in hierarchical relationships with those who take part in their projects, RPPs aim to shift power relations so that all partners have a voice in shaping the work. In this paper we explore discourse practices in RPP meetings to examine how power and voice are shared between researchers and practitioners and how differences might be explained across contexts. Using a framework grounded in practice theory, we conduct quantitative and qualitative analyses of video-recorded meeting data gathered in US and Swiss RPPs, allowing for within- and cross-case comparisons. Comparisons are useful in elucidating how dynamics of voice and power in RPPs play out in contexts where researchers and practitioners may be positioned differently. Our quantitative analysis shows general patterns in which researchers in both RPPs occupy the majority of the speech share, providing some indication for how they share power. In our qualitative analysis we further examine factors influencing power and voice, including meeting topics and materials, and participants' functions in the RPPs and their status within educational systems and universities. While researchers in both RPPs consistently made efforts to engage teachers' voices, this effort alone was not enough to flatten hierarchies given broader relations of power and implicit agreements that influence RPP relationships in both contexts. Implications for further research and practice are discussed.