Research has found that carefully designed professional development opportunities with a focus on pupil outcomes can have a significant impact on student achievement. But how can we ensure that every teacher is able to access high-quality and impactful professional development to benefit them, their pupils and wider society? With articles from international experts including Rob Coe, Becky Allen, David Berliner, Carol Campbell, James Ko and more, accompanied by case studies from a wide range of settings, this report seeks to encourage reflection and support educators everywhere in answering this critical question.