This paper examines the similarities and differences between two successful programmes of teacher professional learning. Firstly, Lesson Study developed in Japan over 40 years ago. It examines practice either through direct observation or through classroom artefacts and case studies. It assumes that teacher learning will be more meaningful and effective if embedded in their everyday work. The core of the process involves working on focus lessons, thus providing a meaningful context for non-threatening lesson observation, and promoting greater collaboration within the group and wider mathematics staff. In Australia, the Lesson Study Project was a state-wide government secondary schools initiative conducted by New South Wales Department of Education and Training for mathematics teachers. It began in 2001, and continues to function even after the ending of direct support from the Department. Secondly, the "Active Mathematics in Primary Schools" (AMIC) Project involves Brunei upper-primary teachers in a large-scale professional development project aimed at assisting them to move away from traditional teacher-centred practices towards methods that engage their students actively in the learning process. In the AMIC Project teachers participate in nine workshops whose content, structures, and materials were fully developed by primary teachers in Brunei Darussalam. Each workshop deals with a "basic" topic nominated by primary teachers in Brunei. After participating in an AMIC workshop, teachers are expected to apply associated ideas in their own classrooms and then report their findings at the next workshop. Because the first major application of AMIC in 2004 proved highly successful it has been continued in 2005. (Contains 1 figure.)