Humblebragging—bragging masked by a complaint-is a distinct and, given the rise of social media, increasingly ubiquitous form of self-promotion. We show that although people often choose to humblebrag when motivated to make a good impression, it is an ineffective self-promotional strategy. Five studies offer both correlational and causal evidence that humblebragging has both global costs-reducing liking and perceived sincerity-and specific costs: it is even ineffective in signaling the specific trait that a person wants to promote. Moreover, humblebragging is less effective than simply complaining, because complainers are at least seen as sincere. Despite people's belief that combining bragging and complaining confers the benefits of both self-promotion strategies, humblebragging fails to pay off.