Founded in 1991, the International Coalition of Girls' Schools (ICGS) is a non-profit membership association serving Pre-K through 12th-grade single-sex girls’ schools across the globe.

In 2022, ICGS agreed to merge with the Alliance of Girls' Schools Australasia.

The combined entity, which will be known as ICGS when the merger is complete at the end of 2023, will include over 500 schools in 18 countries with total enrollment of over 300,000 girls.

[2] In June 2022, the Coalition replaced “National” with “International” in its name, in order to be more inclusive.

A merger with the Alliance of Girls’ Schools Australasia will become official in January 2024.