The purpose of this article is to highlight the importance of public policy on Technical Assistance and Rural Extension (ATER) in promoting sustainable rural development for family farmers. As the research problem, we present the following question: how ATER public policy is related to sustainable rural development for family farmers? To this end, it sought to understand the role of ATER public policy; identify the main guidelines of the National Policy for Technical Assistance and Rural Extension Program (PNATER) that contribute to the sustainable rural development and suggest tools to help ATER to promote sustainable rural development. With bibliographic and documentary support and a qualitative approach, the research provides an overview of bias in updating the ATER legislation and seeing future prospects. In this analysis, which runs along the trajectory of extension in the country, stands out the indicators that support public policies as fundamental tools for their effective implementation. Such implementation includes the use of tools to assist ATER in fostering the development of family farming in three complementary approaches. First is a sustainable approach, a participatory one and a third, which is based on the relationship between ATER/research/teaching, based on dialogic process-oriented communication for rural areas.