The primary purpose of this report was to conduct a critical review of the literature on the application of professional standards to teachers' practice. The New Zealand Teachers Council provided the following questions in the Request for Proposals to guide the review: Where, in the complex mix of factors that can support teachers' professional capacity, do professional standards sit? How can standards support teacher learning? What are the benefits, costs and harms? Which models enhance and which detract from teachers' professional learning and the profession's overall capacity? Can the documented strengths of working with professional standards be gained in other ways?