What is the difference between a Sister City and a Friendship City?

Although the terms Sister City and Friendship City are often used interchangeably, at the City of Austin a Friendship City relationship means a partnership that is more limited in scope. Friendship City relationships are mayor-to-mayor agreements that do not require City Council approval. Sister Cities participate in at least 3 exchanges annually, while Friendship Cities participate in at least one. Only Sister Cities are members of the Austin Sister Cities International committee which meets monthly. Both types of relationships are certified by Sister Cities International and call for long-term commitments from the community.