In 2021, Oregon's legislature passed House Bill 2166, which mandated that the Oregon Department of Education (ODE), in collaboration with the Early Learning Division and the Teacher Standards and Practices Commission (TSPC), develop K-12 Social and Emotional Learning (SEL) standards for students across the state. This manuscript highlights how Oregon used the Transformative SEL framework to guide their multi-phase process, which involved extensive input and collaboration from a diverse group of educators, policy makers, parents and students. This collaborative approach ensured that the standards reflected a wide range of perspectives and addressed the unique needs of various student populations. The manuscript discusses the challenges encountered in the process, such as resistance to change, resource allocation, and professional development needs. This work contributes to the growing body of research on SEL by providing a model for states and districts to develop and implement SEL standards that align with legislative mandates and educational equity goals.