Despite evidence that demonstrates the benefits of school-based sex and relationships education (SRE) in promoting and protecting young people's sexual health, there are still controversies regarding "what" should be covered in the SRE curriculum among different stakeholders, including parents. This study assessed Tanzanian parents' attitudes towards the provision of SRE in schools in order to ascertain their level of support and what they wanted covered in school-based SRE. Two hundred and eighty-seven parents, recruited from one urban district and one rural district, completed a questionnaire assessing their attitudes towards school-based SRE. Results show that, in both districts, more than 75% supported the provision of SRE in schools as well as the inclusion of a wide range of topics in school-based SRE curriculum. However, the results also show that parents do not equally welcome the inclusion of some topics--especially those in the domain of attitudes and values, such as homosexuality and masturbation. The study concludes that, although parents may object to the inclusion of some topics, they generally support the provision of SRE in schools. It is hoped that the results of this study will help to overcome some of the resistance to a more widespread introduction of SRE in Tanzanian schools that rests on fears of parental reaction. (Contains 2 tables, 4 figures, and 1 note.)