This article presents key findings from the Teaching and Learning International Survey (TALIS) conducted in 2007-2008. The aim was to provide comparative insights into the conditions of teaching and learning at their school, the leadership in their schools, their preparation and professional development, and the feedback and appraisal which they do—or do not—receive. TALIS yields important insights into current teaching practices in secondary school as well as teachers’ beliefs and attitudes. TALIS highlights not only that better and more targeted professional development is an important lever toward improvement but also that systems need to do better in matching the costs and benefit as well as supply and demand for professional development.