The purpose of this study was twofold: to find out how teachers of English as an Additional Language (EAL) conceived curriculum, teaching and learning and to examine how professional learning and development (PLD) might impact on changes in the teachers’ thinking and approaches. The research was spurred by my own involvement in the revision of the national New Zealand Curriculum (NZC) and interest in the contested nature of curriculum related to English language learning. EAL teachers face challenges addressing the cross-Learning Area positioning of EAL and, at the same time, are afforded significant autonomy. PLD is needed to support teachers to make curriculum decisions that support English language learners’ (ELLs) to develop competency in English language with urgency. This is because ELLs need to manage the English language demands as they engage in the complex learning that is articulated in the NZC, along with their peers. I adopted an action research methodology to explore both how EAL teachers conceived curriculum and how PLD about EAL teaching and learning might impact on shifts in teachers’ understanding. I was a practitioner-researcher as I carried out PLD for two teachers over a period of six months. Those teacher-participants were teachers of EAL from different secondary schools with different professional contexts. Teaching-as-inquiry was the predominant approach of the PLD. This approach was consistent with my action research. The PLD comprised of a range of interruptions to teachers’ everyday work that assisted them to explore their own practice. The research drew on records of these interruptions to provide evidence of changes in teacher-participants’ thinking. The recorded conversations were captured through semi-structured interviews, video-stimulated recall and ‘learning conversations’. This qualitative data was analysed in one cycle which explored teachers’ thinking and actions about EAL curriculum. A second cycle focused my recorded reflections about my practice and on the impact of particular forms of PLD facilitation on shifts in the teachers’ thinking and actions. I created a review of literature for each cycle. This recursive process allowed me to reflect on my role as a PLD facilitator in action. Several themes emerged as the cycles were drawn together to examine how PLD impacted on shifts in teachers’ understanding of curriculum for EAL. One theme that emerged was the value of a culture of inquiry, where my action research was linked with the participants’ teaching-as-inquiry cycles. Another theme related to how PLD could influence teachers’ reconceptualising of curriculum for teaching multilingual English language learners. A third theme was how my PLD facilitation could impact on effective teaching and learning for Pasifika learners. Findings can be drawn from my study for both teacher practice and for PLD facilitation. This research adds to New Zealand research about teaching ELLs, and Pasifika students in particular. It shows how giving attention to both students’ home language strengths and academic English language learning needs can change the way teachers see pathways and work towards improved outcomes for students. The value of inquiry for teachers was confirmed in this action research, as a useful approach for bring about change in teachers’ thinking and approaches to teaching. The PLD interruption process, which included analysis of rich information about students, challenging conversations and the maintenance of respectful relationships was confirmed as an effective combination for engaging teachers in shifting their foci. Self-reflections on my PLD facilitation role, using an inquiry approach, assessed through adult learning principles, provided a useful stocktake which I would recommend for other PLD facilitators.