The Mathematics Education Research Group of Australasia (MERGA) was founded by John Foyster (then at ACER) and Ken Clements (then at Monash University) in 1976. The first annual conference was held at Monash in 1977 and about 80 people attended. Two volumes of papers were printed. The first annual meeting (held at the end of the Conference) voted almost unanimously to establish MERGA. The second annual MERGA Conference was held at Macquarie in 1978.

The first elected President was Dr Graham Jones, then of Kelvin Grove College of Advanced Education. Graham was President of MERGA for 6 years, and is now a life member.

In 2000, MERGA amalgamated with the Mathematics Education Lecturers Association (MELA), that had begun to hold national conferences from 1976 onwards. This development saw a greater emphasis on teacher education and issues such as teacher supply and retention. As well as the continued production of the Mathematics Education Research Journal (MERJ), a new journal called the Mathematics Teacher Education and Development (MTED) was established.

Currently, MERGA has approximately 570 individual members and 90 institutional members. This membership includes people and institutions from Australia and New Zealand but also from many other countries. There is a growing number of memberships from graduate students.