Sister Cities International

Sister Cities International has worked to create global relationships based on culture, education, information and trade exchanges. Since our founding in 1956, SCI has brought communities across the globe closer together to tackle humanity’s most pressing issues.

Sister city relationships provide mutual benefits to communities far beyond traditional one-off exchanges—they reach every part of their community and improve quality of life.

A sister city, county, or state relationship is a broad-based, long-term partnership between two communities in two countries. A relationship is officially recognized after the highest elected or appointed official from both communities sign off on an agreement to become sister cities.

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500+ Citizen Diplomats and Volunteers


2000+ Worldwide


140+ Connected Internationally