Yes California (originally known as Sovereign California) is a defunct California-based political action committee that promoted the independence of the state of California from the United States of America. Founded in August 2015 by Louis J. Marinelli, a right-wing political activist, the campaign adopted its name and logo from Yes Scotland, a group which advocated for independence during the 2014 independence referendum in Scotland.

The group and its founder faced repeated controversy over the latter's ties to Russia. Both were later implicated in the 2022 federal indictment of a Russian man alleged to have provided support to various California secessionist groups on behalf of the Russian government.

The last instance of secession in the United States was in 1861, a precursor to the formation of the Confederate States of America, when 11 states declared their independence from the Union. The US Constitution lacks any provision for secession. The Supreme Court ruled in Texas v. White in 1869 that no state can unilaterally leave the Union. Secession would require a US Constitutional amendment approved by two-thirds majorities in the US House of Representatives and Senate, then ratification by 38 state legislatures. Analysts consider California's secession improbable.

The hashtag #Calexit trended in social media as the campaign gained attention in the wake of the election of Donald Trump to the presidency in November 2016; California gave Hillary Clinton 61.5% of the vote to Trump's 33.2%. Marinelli asserted this was evidence of the political divide between the state and nation, saying California is more progressive than the rest of the country and that Californians were offended by Trump's statements about minorities.

The campaign staged protests outside the Capitol building in Sacramento after the November 2016 election, though its organizers asserted the protests had been planned months in advance and would have been held, regardless of who won the election. Immediately following the election, the campaign received 11,000 emails.

On November 21, 2016, the Yes California campaign submitted an initiative for signature gathering, with an amendment sent later on December 23 to correct a typo. If passed by voters in November 2018, it would have repealed Article III, Section 1 of the California Constitution, which states California is "an inseparable part" of the U.S., and require an independence plebiscite to be held on March 5, 2019, on the question of California's independence, the passage of which would have required at a minimum 50% voter turnout and 55% voting yes. If the proposed 2019 independence referendum had passed, the Governor of California would have then been required to apply for California to join the United Nations.

On January 26, 2017, the office of California Secretary of State Alex Padilla gave its approval for the signature gathering process to begin.

The Washington Post reported on February 18 that the Yes California campaign had opened up to 53 chapters across the state, but had not yet reported contributions to the California Secretary of State's office.