This list is by no means exhaustive. I collected the lists from sources like ALA, SAA, Wikipedia, and googling. I will add new organizations as I find them.
ALA Organizations
- American Library Association (ALA)
- American Association of School Librarians (AASL)
- Association for Library Collections & Technical Services (ALCTS)
- Association for Library Service to Children (ALSC)
- Association of College and Research Libraries (ACRL)
- Association of Specialized, Government & Cooperative Library Agencies (ASGCLA)
- Library Information Technology Association (LITA)
- Library Leadership & Management Association (LLAMA)
- Public Library Association (PLA)
- Reference & User Services Association (RUSA)
- United for Libraries (Trustees, Friends, Foundations)
- Young Adult Library Services Association (YALSA)
ALA Affiliates
- American Association of Law Libraries (AALL)
- American Indian Library Association
- Association for Information Science and Technology
- American Theological Library Association
- Art Libraries Society of North America (ARLIS/NA)
- Asian/Pacific American Librarians Association
- Association for Library and Information Science Education
- Association for Rural and Small Libraries
- Association of Bookmobile and Outreach Services
- Association of Jewish Libraries
- Association of Research Libraries (ARL)
- Beta Phi Mu
- Black Caucus of ALA
- Catholic Library Association
- Chinese American Librarians Association
- The Joint Council of Librarians of Color
- Latino Literacy Now
- Library and Information Association of New Zealand Aotearoa
- Medical Library Association
- Music Library Association
- National Storytelling Network
- Online Audiovisual Catalogers
- Patent and Trademark Resource Center Association
- ProLiteracy Worldwide
- REFORMA
- Seminar on the Acquisition of Latin American Library Materials
- Theatre Library Association
Non-ALA Organizations
- Association of Architecture School Librarians
- Association of Moving Image Archivists
- National Association of Government Archives & Records Administrators
- North American Serials Interest Group (NASIG)
- Society of American Archivists
- United States Agricultural Information Network
- Western Association of Map Libraries
International Organizations
- Association of Caribbean University, Research and Institutional Libraries
- Canadian Association for Information Science (CAIS-ACSI)
- Canadian Health Libraries Association
- Ontario Library Association (OLA)
Regional Organizations
- Border Regional Library Association (BRLA)
- Mountain Plains Library Association
- Southeastern Library Association
State & State Government-Associated Organizations
- Alaska
- Arizona
- Arkansas
- California
- Connecticut
- Delaware
- District of Columbia
- Hawaii
- Indiana
- Kansas
- Kentucky
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Montana
- Nebraska
- Nevada
- New Jersey
- New Mexico
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming