| Alameda | City of Alameda | Alameda Sister Cities Association |
| Antioch | | Antioch-Chichibu Sister City Organization |
| Arcata | City of Arcata | Arcata-Camoapa Sister City Project |
| Benicia | City of Benicia | Benicia-Tula Sister Cities |
| Berkeley | City of Berkeley | Berkeley-Palma Soriano Sister City Association
Berkeley-Sakai Association |
| Brisbane | | |
| Campbell | | Sister Cities of Campbell |
| Coloma | Coloma / County of El Dorado | |
| Concord | City of Concord
| Concord Ambassadors
|
| Crescent City | | |
| Cupertino | City of Cupertino | Cupertino Bhubaneswar Sister City Initiative
Cupertino Copertino Sister Cities Association
Cupertino-Hsinchu Sister City Association
Cupertino-Toyokawa Sister City Program |
| Daly City | | |
| Davis | City of Davis
| |
| Dublin | | Dublin Sister Cities Association
|
| Elk Grove | City of Elk Grove | |
| Eureka | City of Eureka
| |
| Fairfield | City of Fairfield
| Fairfield-Nirasaki Sister City Program
|
| Folsom | | Folsom-Pieve del Grappa Sister City Friends
|
| Fort Bragg | | Fort Bragg Otsuchi Exchange |
| Foster City | City of Foster City | Foster City Sister City Association |
| Fremont | | |
| Fresno | | Fresno Sister Cities
Fresno-Châteauroux Sister Cities International
Fresno-Verona Sister Cities Program |
| Gilroy | | Gilroy Sister Cities Association
|
| Gonzales | City of Gonzales | |
| Grass Valley | City of Grass Valley | |
| Greenfield | | |
| Gustine | | |
| Hayward | | Funabashi-Hayward Sister City Committee
Hayward Faro Sister City Committee
Hayward-Ghazni Sister Cities
Hayward San Felipe Sister City Committee
Hayward-Yixing Sister City Committee Inc. |
| Hercules | City of Hercules
| |
| Hollister | | Hollister Sister City Association |
| Kerman | City of Kerman | |
| Lathrop | | |
| Livermore | City of Livermore | Livermore Yotsukaido Sister City Organization |
| Livingston | | |
| Lodi | City of Lodi | |
| Los Gatos | | |
| Madera | | Madera-Ilan Sister City Corporation |
| Martinez | City of Martinez | Martinez - Dunbar Sister City |
| Marysville | | Marysville-Peikang Sister City Association Inc. |
| Mendocino | | Mendocino Sister Cities Association |
| Menlo Park | City of Menlo Park | Menlo Park Sister Cities Association |
| Merced | | Hearts Afire Foundation - Somoto, Nicaragua |
| Millbrae | City of Millbrae | |
| Milpitas | City of Milpitas | |
| Modesto | City of Modesto | Modesto Sister Cities International |
| Monterey | City of Monterey | |
| Morgan Hill | | Morgan Hill Sister Cities Association |
| Mountain View | City of Mountain View | |
| Napa | City of Napa | |
| Nevada City | | |
| Novato | | |
| Oakland | | Oakland - Fukuoka Sister City Association |
| Orinda | City of Orinda | The Orinda and Tabor Sister City Foundation |
| Pacifica | | |
| Palo Alto | City of Palo Alto | Neighbors Abroad Palo Alto Sister Cities |
| Parlier | | |
| Pittsburg | City of Pittsburg | |
| Placer County | | |
| Placerville | City of Placerville | |
| Pleasant Hill | City of Pleasant Hill | |
| Pleasanton | | Pleasanton - Blairgowrie - Fergus Sister City Organization
Pleasanton-Tulancingo Sister City Association |
| Rancho Cordova | | Rancho Cordova Sister Cities Council, Inc. |
| Redwood City | City of Redwood City | Redwood City International |
| Richmond | City of Richmond | |
| Rio Vista | City of Rio Vista | |
| Riverbank | | |
| Rohnert Park | City of Rohnert Park | |
| Roseville | | |
| Sacramento | | Sacramento Ashkelon Sister City
SacramentoBethlehem
Hamilton - Sacramento Sister City Corporation
Jinan Sacramento Sister Cities Corporation
|
| Salinas | City of Salinas | Salinas-Ichikikushikino Sister City Association |
| San Bruno | City of San Bruno | |
| San Carlos | | San Carlos Sister City Association |
| San Francisco | City and County of San Francisco | San Francisco - Bangalore Sister City Initiative
San Francisco - Cork Sister City Program
San Francisco - Ho Chi Minh City Sister City Committee
San Francisco - Kraków Sister Cities Association
San Francisco - Osaka Sister City Association
San Francisco - Taipei Sister City Committee
San Francisco - Zürich Sister City Committee |
| San Jose | City of San Jose | San Jose - Tainan Sister City Association
San Jose - Okayama Sister Cities
San Jose - Dublin Sister City Program
San Jose - Pune Sister City
|
| San Leandro | City of San Leandro | |
| San Mateo | City of San Mateo | Toyonaka - San Mateo Sister City Association |
| San Pablo | | San Pablo - Manzanillo Sister Cities |
| San Rafael | City of San Rafael | |
| Santa Clara | City of Santa Clara | Santa Clara Sister Cities Association |
| Santa Clara County | County of Santa Clara | |
| Santa Cruz | City of Santa Cruz | |
| Santa Rosa | City of Santa Rosa | |
| Saratoga | | Saratoga Sister City |
| Sausalito | | Sausalito Sister Cities |
| Seaside | | |
| Sebastopol | City of Sebastopol | Sebastopol World Friends |
| Scotts Valley | | |
| Sonoma | City of Sonoma | Sonoma Sister Cities Association |
| Sonora | City of Sonora | |
| South Lake Tahoe | | |
| South San Francisco | City of South San Francisco | South San Francisco Sister Cities |
| Stockton | City of Stockton | Stockton Sister Cities Association |
| Suisun City | | |
| Sunnyvale | | Sunnyvale Sister City Association |
| Tracy | | Sister City Association of Tracy |
| Truckee | | |
| Union City | | Union City Friends of Sister Cities |
| Vallejo | City of Vallejo | Vallejo Sister City Association |
| Walnut Creek | | Walnut Creek Sister Cities International |
| Watsonville | City of Watsonville | Kawakami-Watsonville Sister City Association |
| West Sacramento | | |
| Woodland | | |
| Yolo County | | |
| Yountville | | |
| Yuba City | | Yuba City Sister City Association |
