Online-video advertising is growing rapidly, yet advertisers and Web site owners might not be accounting for the potentially negative impact of these advertisements. The current study examined the effects of advertisement characteristics—such as length, humor, and informativeness—on perceived ad intrusiveness and, subsequently, on marketing outcomes for both online advertisers and Web site owners. Results showed that intrusive advertisements negatively affected attitudes and intentions toward both the advertised brand and the host Web site. Informative and humorous video advertisements and longer advertisements, however, were perceived as less intrusive. The results implied that advertisers need to pretest video advertisements rigorously to achieve optimal marketing outcomes.