There is a growing phenomenon of brand advocacy, where brands pressure a producer country government to take pro‐worker actions such as respecting the rights of activists and raising minimum wages. This article examines the potential and limits of brand advocacy by developing a conceptual framework and analysing three recent cases of brand advocacy in Cambodia's garment industry. The study shows that brands' action and influence are shaped by issue salience, mobilization structures, political opportunities/contexts, and resource dependency. This article makes both empirical and theoretical contributions. This is one of the first studies delving into the advocacy role of brands in promoting labour rights and conditions vis‐à‐vis government. Moreover, the article develops a testable framework specifying the conditions under which brands are likely to respond, act collectively, and influence government for pro‐worker change. It also offers novel insights by applying social movement lenses and casting brands as social movement actors.