AbstractPurpose Fourteen U.S. states and the District of Columbia have banned handheld phone use for all drivers. We examined whether such legislation was associated with reduced handheld phone conversations among drivers < 25 years of age. Methods Data from the 2008-2013 National Occupant Protection Use Survey were merged with states' legislation. The outcome was roadside-observed handheld phone conversation at stop signs or lights. Logistic regression was used. Results A total of 32,784 young drivers were observed. Relative to drivers who were observed in states without a universal handheld phone ban, the adjusted odds ratio (aOR) of phone conversation was 0.42 (95% confidence interval CI: 0.33, 0.53) for drivers who were observed in states with bans. The relative reduction in phone conversation was 46% (23%, 61%) for laws that were effective < 1 year, 55% (32%, 70%) for 1-2 years, 63% (51%, 72%) for ≥ 2 years, relative to no laws. Conclusions Universal handheld phone bans may be effective at reducing handheld phone use among young drivers.