Research has identified critical thinking to be important for short and long term student achievement, but there appears to be inconsistent theoretical understanding and pedagogical approaches to its transfer (Abrami et al., 2015). Even with a perceived value of critical thinking embedded in the minds of educators, and its prominence among the objectives of school curriculums across sectors, there is a gap of research that specifically focuses on how it is perceived and developed in Secondary School classrooms (Davies & Meissel, 2015). This presentation will share mixed methods research findings of how 28 New Zealand secondary teachers across the subject areas of English, Science and Social Science perceive and develop critical thinking as part of their instructional practice. It will also explore the outcomes of what a professional development focus on critical thinking has in supporting or shifting their views and practices. It is through these outcomes that this presentation hopes to empower educators to explore and develop their models of best practice, as well as help ensure secondary students receive purposeful critical thinking instruction.