Background. Improving HPV vaccination coverage in the US will require healthcare providers to recommend the vaccine more effectively. To inform quality improvement efforts, we systematically reviewed studies of provider communication about HPV vaccination. Methods. We searched MEDLINE, CINAHL, EMBASE, and POPLINE in August 2015 to identify studies of provider communication about HPV vaccination. Results. We identified 101 qualitative and quantitative studies. Providers less often recommended HPV vaccine if they were uncomfortable discussing sex, perceived parents as hesitant, or believed patients to be low risk. Patients less often received recommendations if they were younger, male, or from racial/ethnic minorities. Despite parents' preference for unambiguous recommendations, providers often sent mixed messages by failing to endorse HPV vaccine strongly, differentiating it from other vaccines, and presenting it as an "optional" vaccine that could be delayed. Conclusion. Interventions are needed to help providers deliver effective recommendations in the complex communication environment surrounding HPV vaccination.