Human papilloma virus (HPV), one of the most common sexually transmitted infections, is preventable through a vaccine now recommended for all females and males age 11 to 26. However, vaccination rates remain low in the U.S., in part because only one-third of doctors prescribe the vaccine to eligible patients. HPV infection can lead to genital warts and certain types of cancer. This brief provides an analysis of the current state of HPV vaccination rates in the U.S., finding them lagging well behind other countries, where vaccination campaigns have been more successful.