In Australia, students on the autism spectrum are increasingly being educated in inclusive settings. However, many teachers in mainstream educational settings do not feel they have the specialised knowledge or skills required for inclusive teaching of students on the autism spectrum. Teacher knowledge and confidence can influence the educational success of students on the autism spectrum, inclusive school practices, and teacher competency. Accessible and relevant evidence-based professional development can be an effective way of improving teachers’ competency for developing student social emotional, behavioural, communication, sensory, and learning skills. This chapter discusses a large school-based research project that used a Design-Based Research approach to design, validate, and trial two Models of Practice (MoP) for mainstream early and middle educators in Queensland, New South Wales, and Victoria. An MoP is a universally designed, evidence-based set of whole-class strategies for teachers which supports teachers to choose the most appropriate practices for fostering the inclusion of students on the spectrum. It also guides teacher decision-making and practice for curriculum content such as individualised lessons, and managing learning environments so as to provide an autism-friendly classroom infrastructure, social emotional adjustments, and behavioural supports. This chapter provides discussion and examples on how these practices can be supported in the classroom. Comments from participating teachers are included in this chapter to provide insightful suggestions for using the MoP briefs.