The emerging literature on research-practice partnerships in education explains the conditions under which these partnerships operate to achieve the desired impact. This study adds to that literature base by exploring variation in the perceived impacts across three partnerships whose goal was improving achievement for multilingual learner students. To examine these partnerships, we posit a conceptual framework that defines partnership impacts and associated supportive dynamics within the partnership. We use this framework to guide our analysis of interviews and observations from three partnerships. Our study finds (1) practitioners and researchers' motivations to engage in the RPP are different but complementary; (2) practitioners and researchers perceive the RPP as impacting their capacity either to make decisions that change policy and practice or to develop research that is relevant for theory and practice; (3) both researchers and practitioners agree that consistent communication through meetings and reliable funding supports the RPP. Implications for the field and ideas for further research are discussed.