OER Knowledge CloudConference Paper20172017/07Butler, DeirdreLeahy, MargaretHallissy, MichaelBrown, MarkTatnall, ArthurWebb, Maryteacher educationonline learningMOOCs21st century skillsIrelandSpringer International Publishing149–160978-3-319-74310-3This paper describes the most recent phase of an innovative model of teacher professional learning that has evolved over a decade (2006 to 2016). Building on the experiences of implementing this face-to-face model, the paper reports on the most recent phase which attempts to harness the emergence of a 4th wave of online learning. The initiative involves the design and development of a Massive Open Online Course (MOOC) that potentially enables the massive scaling up of access to this already validated model of teacher professional learning designed to shift teachers' pedagogical orientations through school focussed, job embedded teacher professional learning. The importance of maintaining key elements, threshold concepts and signature pedagogies in the design of MOOCs for teacher professional learning are discussed. The paper also explores some of the challenges and potential opportunities different MOOC delivery models offer for sustaining the types of collaboration, rich dialogue and ongoing reflection observed in earlier phases of the project.yes10.1007/978-3-319-74310-3_17Dublin, Ireland