In 2015 mandatory disclosure activity for lobbying that targeted health and social service centres in Quebec, a sector which consumes a significant share of the annual spending budget, suddenly became a mandatory disclosure activity for lobbyists operating in the province. This research note traces the trajectory of key events that led to this shift towards greater lobbying transparency in the health care sector. The study also analyzes whether this change was followed by increased lobbying registrations for activities targeting health sector institutions. The article's findings suggest that significant change in lobbying regulation may occur accidentally, against the government's will, rather than as a result of an ethical scandal, cross‐jurisdictional learning, or electoral calculations, as the literature suggests. The article's findings also show that the change was followed by an increase of about 969 registered firm lobbyists (p‐value 0.015) and 254 registered lobbyists from covered NGOs (p‐value 0.00).