Comprehensive sexuality education (CSE), one of the key evidence-based strategies in our programmatic toolbox to address adolescent pregnancy and birth rates, remains a politically-charged issue countrywide. Though there is some funding available at the federal level, there are no national policies mandating the provision of sex education; as such, most decision-making occurs at the state or even the local level. Consequently, the provision of sex education and the quality and comprehensiveness of curricula used to do so are highly variable across the country, and are heavily influenced by the level of support or resistance in communities. This paper analyzes the experience of institutionalizing an evidence-based sex education in a large suburban school district in San Antonio, Texas, a socially conservative context. Understanding the politics of sex education is key to developing effective policies and strategies to ensure quality sex education programs are provided in public schools. However, there are no published papers documenting specific experiences with resistance to sex education in local communities in the USA. Given this, the strategies employed by opponents and the response by district officials can be informative for other school settings in the USA and around the world.