Physicians played a key role in advancing Canada’s recent assault weapons ban. Indeed, after announcing the ban in May 2020, the Trudeau government thanked Dr. Najma Ahmed and the group Canadian Doctors for Protection from Guns (CDPG) for their support of responsible gun control measures. In this piece, we explore the context in which CDPG was formed, the strategies used by the group in building nationwide support for gun control measures, and the public health framing of their messaging that proved critical in engendering political change. The work of CDPG holds valuable lessons for physicians seeking to engage in political advocacy by bearing witness to the harms experienced by their patients.