The goal of this paper, "National Sexuality Education Standards: Core Content and Skills, K-12," is to provide clear, consistent and straightforward guidance on the "essential minimum, core content" for sexuality education that is developmentally and age-appropriate for students in grades K-12. The development of these standards is a result of an ongoing initiative, the Future of Sex Education (FoSE). Forty individuals from the fields of health education, sexuality education, public health, public policy, philanthropy and advocacy convened for a two-day meeting in December 2008 to create a strategic plan for sexuality education policy and implementation. A key strategic priority that emerged from this work was the creation of national sexuality education standards to advance the implementation of sexuality education in US public schools. Specifically, the "National Sexuality Education Standards" were developed to address the inconsistent implementation of sexuality education nationwide and the limited time allocated to teaching the topic. Health education, which typically covers a broad range of topics including sexuality education, is given very little time in the school curriculum. A glossary is included.