國外締結合作之學校
茗溪學園與代表著各國之學校締結合作，進行著6個月至1年之交換留學、學術交流、文化交流、運動交流等多樣交流活動。
海外提携校
Indonesia
Raffles Christian School
Malaysia
King Henry VIII College
New Zealand
Nelson College
Nelson College for Girls
Macleans College
Thailand
Chulalongkorn University
Demonstration Secondary School
Patumwan Demonstration School, Srinakharinwirot University
Vietnam
The Foreign Language Specialized School, University of Languages & International Studies, Vietnam National University
Hanoi Japan International School
The United Kingdom
Christ College
海外交流校
Australia
Knox Grammar School
St Josephs College
China
Weiyu High School
Hong Kong
Diocesan Boys’ School
Malaysia
Chung Ling High School
New Zealand
Edgewater College
Waimea College
Otago Boys’ High School
Otago Girls’ High School
Singapore
St. Joseph’s Institute
Thailand
Srinakarinwirot University Prasarnmit Demonstration School (Secondary)
Taiwan
Taichung Municipal Taichung Girls
Senior High School
Vietnam
The ULIS Middle School (UMS), the University of Languages and International Studies, Vietnam National University
The United Kingdom
Bristol Grammar School