During the 1980s, homeless people formed social movement organizations and mobilized collective action events in cities across the US. From the vantage point of social movement theories and scholarship on homelessness, it is surprising that homeless protest was so prevalent in the 1980s. Yet we find evidence of homeless protest events across no fewer than 50 U.S. cities in the 1980-90 period. Drawing on social movement theories about the precipitants of mobilization, we examine the extent to which city-level contextual factors, and their change over time, affect variation in the frequency of homeless mobilization across 17 of these cities. Our findings reveal that a mix of factors congruent with strain and resource mobilization theories helps to account for variation in the frequency of homeless protest across U.S. cities in the 1980s.