Electronic cigarettes (e-cigarettes) are the most frequently used tobacco product among U.S. youths, and past 30-day e-cigarette use is more prevalent among high school students than among adults (1,2). E-cigarettes typically deliver nicotine, and the U.S. Surgeon General has concluded that nicotine exposure during adolescence can cause addiction and can harm the developing adolescent brain (2). Through authority granted by the Family Smoking Prevention and Tobacco Control Act, the Food and Drug Administration (FDA) prohibits e-cigarette sales to minors, free samples, and vending machine sales, except in adult-only facilities (3). States, localities, territories, and tribes maintain broad authority to adopt additional or more stringent requirements regarding tobacco product use, sales, marketing, and other topics (2,4). To understand the current e-cigarette policy landscape in the United States, CDC assessed state and territorial laws that 1) prohibit e-cigarette use and conventional tobacco smoking indoors in restaurants, bars, and worksites; 2) require a retail license to sell e-cigarettes; 3) prohibit e-cigarette self-service displays (e.g., requirement that products be kept behind the counter or in a locked box); 4) establish 21 years as the minimum age of purchase for all tobacco products, including e-cigarettes (tobacco-21); and 5) apply an excise tax to e-cigarettes. As of September 30, 2017, eight states, the District of Columbia (DC), and Puerto Rico prohibited indoor e-cigarette use and smoking in indoor areas of restaurants, bars, and worksites; 16 states, DC, and the U.S. Virgin Islands required a retail license to sell e-cigarettes; 26 states prohibited e-cigarette self-service displays; five states, DC, and Guam had tobacco-21 laws; and eight states, DC, Puerto Rico, and the U.S. Virgin Islands taxed e-cigarettes. Sixteen states had none of the assessed laws. A comprehensive approach that combines state-level strategies to reduce youths' initiation of e-cigarettes and population exposure to e-cigarette aerosol, coupled with federal regulation, could help reduce health risks posed by e-cigarettes among youths (2,5).