BACKGROUND: Researchers in several studies have examined correlations between tobacco harm perceptions and tobacco use in youth, but none have prospectively addressed the association between harm perceptions and subsequent new use across multiple noncigarette products. METHODS: Product-specific absolute and relative harm perceptions for cigarettes, electronic cigarettes (e-cigarettes), cigars, pipes, hookah, and smokeless tobacco were collected at wave 1 (W1) (2013–2014) among youth in the nationally representative US Population Assessment of Tobacco and Health Study (12–17 years of age; n = 10 081). At wave 2 (W2) (2014–2015), product-specific new use was calculated. Adjusted relative risks were used to estimate if harm perceptions at W1 predicted W2 new tobacco use. RESULTS: The proportion of youth who endorsed “a lot of harm” was highest for cigarettes (84.8%) and lowest for e-cigarettes (26.6%); the proportion of youth who thought products were “more harmful” than cigarettes was highest for cigars (30.6%) and lowest for e-cigarettes (5.1%). Among youth who had not used those products at W1, product-specific new use at W2 ranged from 9.1% (e-cigarettes) to 0.6% (pipes). Youth who believed that noncombustible tobacco products posed “no or little harm” at W1 were more likely to have tried those products at W2 (P < .05). Youth who viewed e-cigarettes, hookah, and smokeless tobacco as “less harmful” than cigarettes at W1 were more likely to try those tobacco products at W2 (P < .05). CONCLUSIONS: Low harm perceptions of noncigarette tobacco products predict new use of these products by youth within the next year. Targeting product-specific harm perceptions may prevent new tobacco use among youth.