- American Federation of State, County, and Municipal Employees (AFSCME)
- Extra Help AFSCME & SEIU
- Building and Construction Trades Council (BCTC)
- California Nurses Association (CNA)
- Deputy Sheriff’s Association (DSA)
- Law Enforcement Unit (DSA Non-Safety) Classifications (LEU)
- Organization of Sheriff’s Lieutenants (OSL)
- Organization of Sheriff’s Sergeants (OSS)
- Probation & Detention Association (PDA)
- San Mateo County Council of Engineers (SMCCE)
- Service Employees International Union (SEIU)
- Union of American Physicians and Dentists (UAPD)