Labor unions play a prominent role in the economy and in politics, and have long been depicted by opponents as an overly powerful, corrupt and economically harmful institution. In labor-related news in recent years, anti-union rhetoric has regularly focused on union workers themselves, frequently portraying them as overpaid, greedy and undeserving of their wealth, while also drawing a contrast between the compensation of union vs. non-union workers. This type of rhetoric is referred to here as class-based anti-union rhetoric (CAR). Despite its prevalence, it remains unknown whether CAR affects public opinion toward unions. This study uses a series of national survey experiments to demonstrate that exposure to CAR reduces the perceived similarity of targeted union workers, unions’ perceived deservingness of public support and support for pro-union legislation. Moreover, CAR repeatedly nullified or reversed the otherwise positive relationship between the strength of worker identity and solidarity with union workers.