This article describes the challenge of engaging educators in professional development (PD) that is timely and relevant to their work, and effective in stimulating instructional changes to improve student learning. The authors highlight the competing needs and goals for PD that create tensions among the external accountability demands, school improvement goals, and the diverse and context-dependent professional learning needs of teachers. Two examples of large-scale PD initiatives in the US are described to illuminate how state accountability goals shaped these efforts, how teachers were engaged in PD, what factors or elements increased the relevancy and quality of the PD, and how leaders at various levels supported teachers' learning. These cases provide further insights about the role and challenges for leadership at the state, university and local levels to support and implement high quality PD. The authors argue that leadership plays a central role aligning accountability needs and teachers' professional learning needs and that technology, through hybrid and online learning environments, can support high quality PD that is customised for the needs of teachers and schools.