Rockville Sister City Corporation was formed when Rockville’s Sister City relationship with Pinneberg, Germany was established in 1957. In 1986 it was incorporated into a 501(c)(3) nonprofit organization with a mission to support educational and charitable programs and to facilitate the continuing relationship between the citizens of Rockville and of Pinneberg, Germany.
In 2009 a "Friendship Agreement" was signed between the City of Rockville and Jiaxing, China. Correspondence, exchanges and cultural activities between Rockville and Pinneberg as well as Rockville and Jiaxing are overseen by the Rockville Sister City Corporation. In accordance with its bylaws, the Mayor and Council appoint three directors. The remaining directors are elected by its membership. Terms are for three years and are staggered. Membership in the corporation is open. In 2017 Rockville celebrated its 60th anniversary with Pinneberg and in 2019, will celebrate its 10th anniversary with Jiaxing.