The Friends of Weyenberg Library (FOWL) is a 501c3 non-profit organization dedicated to supporting the Frank L. Weyenberg Library of Mequon-Thiensville. FOWL enhances Library services with volunteers for special events and on-going projects, funds for Library extras, including annual Summer Reading Programs, Book Club Kits, family BINGO events, and more. Advocacy for Library services, locally, state-wide, and nationally.

Since 1999, Mequon-Thiensville Community Foundation, a non-profit, has awarded over $1.1 million to enhance the quality of life in Mequon and Thiensville. The majority of their grants support programs within three pillars: Municipality, Historical, and Parks & Recreation.

Thiensville-Mequon Rotary Club is a member of Rotary International, meeting at noon on Tuesdays in Mequon.

An independent, non-profit organization created to provide financial support to the Southern Ozaukee Fire Department and other community organizations.