The global learning crisis has highlighted the urgent need to improve the quality of education. COVID-19 disruptions have placed even greater focus on the learning improvement agenda, and the need to ensure disadvantaged children are not further left behind. Teacher development, and improving teaching quality, therefore is at the heart of many education systems’ policies and programs. This paper presents some of the key considerations for improving teaching across three countries which are being investigated as part of a multi-year teacher development study series. This study series, commissioned by the Australian Government’s Department of Foreign Affairs and Trade (DFAT), involves the investigation of teacher development initiatives in Timor-Leste, Vanuatu and Lao People’s Democratic Republic (Laos). The overall aim of each study is to investigate: To what extent does the Australian investment produce improved teaching quality and improved student learning? The paper first provides a synopsis of each country context and the DFAT teacher development investment. It then provides an overview of each country study. Each study uses a mixed methods approach, are multi-year, and at different stages. Finally, it discusses four emerging themes that contribute to enabling or constraining the success of the teacher development investments.