Background: Protests against police brutality and anti-Black racism were catalyzed by the murder of George Floyd and other Black and racialized people in spring 2020. Addressing anti-Black racism had been historically minimized as an institutional priority across Canadian medical schools, but many swiftly released statements broadly condemning racism. Given that little has been documented about how institutions are responding with action, we sought to explore Black medical students' and senior faculty perspectives on Canadian medical schools' efforts to address anti-Black racism in 2020. Methods: We conducted a qualitative, instrumental case study, grounded in critical race theory. We recruited Black medical students and deans (or delegated senior faculty administrators) and we conducted virtual, individual, semi-structured interviews with participants between Oct. 5, 2020, and Jan. 16, 2021. Interviews were transcribed and iteratively analyzed through inductive and deductive techniques. Results: We interviewed 19 participants, including 8 medical students (6 in pre-clerkship; all of whom identified as Black) and 11 senior faculty administrators (4 deans, 7 delegate faculty administrators; 3 racialized). We had at least 1 student or faculty participant from 13 medical schools, and no student or faculty participants from the 4 medical schools in Quebec. Nearly all represented medical schools were described as "starting from scratch" in their responses, having previously failed to acknowledge or address anti-Black racism. In the absence of diverse faculty leaders, participants indicated that medical schools primarily relied on Black medical students to drive institutional responses, unfairly burdening students during an already difficult period. At the time of the interviews, a range of initiatives were in the planning stages or underway, and were largely related to admissions and curriculum reform. Interpretation: We found that medical schools relied heavily on Black medical students to inform and drive their institutional responses related to anti-Black racism in 2020, which these students found burdensome. Medical schools lacked intrinsic capacity because of the paucity of Black faculty--a direct result of historical and ongoing structural anti-Black racism in medicine. Institutional accountability remains critical, and further research is needed to show the extent to which medical schools in Canada are successfully addressing anti-Black racism.