Since the end of the Cold War, international organizations (IOs) have engaged in unprecedented levels of democracy promotion, and research overwhelmingly links them to positive democratic outcomes. However, this increased emphasis on democracy has more recently been accompanied by rampant illiberalism and a sharp rise in cases of democratic backsliding in new democracies. What explains democratic backsliding in an age of unparalleled international support for democracy? Backsliding occurs when democratic institutions are weakened or eroded by elected officials, resulting in an illiberal or diminished form of democracy. I argue that IOs that support democracy unintentionally make backsliding more likely by neglecting to promote democratic institutions other than executives and elections, increasing executive power, and limiting states’ domestic policy options, which stunts institutional development. I find membership in IOs associated with democracy promotion makes backsliding more likely, decreases checks on executive power, and limits domestic policy options and party development in new democracies.