California Proposition 1

California Proposition 1 may refer to:


 * 1998 California Proposition 1, concerning property tax valuation
 * 1998 California Proposition 1A, concerning bonds related to education
 * 2004 California Proposition 1A, concerning revenue collected by local government
 * 2006 California Propositions 1A–E, concerning taxes and bonds for several programs
 * 2008 California Proposition 1A, concerning high-speed rail
 * 2009 California Propositions 1A–F, concerning several reforms to state law
 * 2014 California Proposition 1, concerning bonds to upgrade California's water system
 * 2018 California Proposition 1, concerning veterans' home loans and affordable housing
 * 2022 California Proposition 1, concerning abortion and contraception
 * 2024 California Proposition 1, concerning mental health treatment