ICMI Members are neither individuals nor organizations, but countries. In the following, we use the notion of “country” as defined in the IMU Statutes (Article 4): “The term ‘country’ is to be understood as including diplomatic protectorates and any territory in which independent scientific activity in mathematics has been developed, and in general shall be construed as to secure the broadest and most effective participation of mathematicians in the scientific work of the Union.”

All IMU member countries are de facto ICMI members. The IMU Adhering Organization of the country (typically the academy of science, the mathematical society or similar institution) is responsible for nominating the ICMI Country Representative, in consultation with prominent members of the local mathematics education communities.

It is possible for a country unable to join IMU to be co-opted by ICMI. This requires the approval of both ICMI and IMU Executive Committees, under item (8) in the ICMI Terms of Reference. When considering an application for membership from a non-IMU country, the ICMI EC looks for evidence within the country seeking membership of coordinated involvement from major parties in mathematics education, such as organizations of university and research mathematicians, researchers in mathematics education, teachers of mathematics, and so on according to the specific circumstances. If the application is successful, a body (normally the body responsible for the application) will be identified as an equivalent of the IMU Adhering Organization with respect to ICMI. In particular, this body is responsible for nominating the ICMI Country Representative.

There are currently about 90 ICMI member countries, more than 80 of which are also members or associate members of IMU. Each ICMI Country Representative, whether from an IMU member country or not, participates in the election of the ICMI Executive Committee (on a quadrennial basis) during the ICMI General Assembly.
No Country Representative may serve for more than two consecutive four-year terms (Kobe Rule). 

Here you can find out more about the role of the ICMI representatives (pdf file).

Here is the list of all ICMI Country Representatives, with the non IMU countries marked with an *.

ICMI is in the process of creating a page describing the context of mathematics education in each ICMI Member Country. When it exists, you can access this page by clicking on the name of the country in the list of Country Representative or at the end of the website in the “Around ICMI” menu.