Art museums are responding to increasing calls for exhibitions, community engagement, and institutional change that confront and unsettle taken-for-granted narratives, knowledge, policies, and practices. Grounded in my work as a mid-career gallery educator and trainer, this qualitative study asks what gallery educators’ learning looks like and what motivates it. How does it shape or respond to change?  Through this line of inquiry, I sought to better understand how myriad paths to competency building can support or hinder critical gallery dialogue, an ethos of social justice, and wider efforts to make art museums more representative, responsive, and relevant to the publics they are meant to serve. 
This manuscript-based thesis draws on tenets of critical pragmatism, transformative adult learning, and constructivist grounded theory to analyze individual and group interviews with gallery educators in Canada and Scotland. The first manuscript examines how volunteer guides identify, navigate, and reflect on challenging subject matter in both their ongoing learning and gallery dialogue with visitors. The second manuscript focuses on freelance gallery educators’ professional learning within the overlapping contexts of the coronavirus pandemic and protests for racial justice in 2020. The third and final manuscript considers the potential for gallery educators’ informal professional learning to inform internal policies and procedures. 
I link the three manuscripts with a prelude that highlights gallery educators’ learning as they describe it and two bridging texts that situate my findings in their wider contexts. These self-reflexive texts, which address decolonial turns and whiteness in art museums, draw on additional literature and my own professional learning trajectory over the duration of my doctoral studies. I conclude with final reflections on transformation as a theoretical starting point, learning through the writing process, and implications for future research. This thesis contributes to both a paucity of scholarly research on critical professional learning in art museums and an emerging body of literature addressing the impacts of a global pandemic on museum workers.