The California Public Employees' Retirement System (CalPERS) is an agency in the California executive branch that "manages pension and health benefits for more than 1.5 million California public employees, retirees, and their families". In fiscal year 2020–21, CalPERS paid over $27.4 billion in retirement benefits, and over $9.74 billion in health benefits.

CalPERS manages the largest public pension fund in the United States, with more than $469 billion in assets under management as of June 30, 2021. CalPERS is known for its shareholder activism; stocks placed on its "Focus List" may perform better than other stocks, which has given rise to the term "CalPERS effect". Outside the U.S., CalPERS has been called "a recognized global leader in the investment industry", and "one of America's most powerful shareholder bodies".

As of 2018, the agency has $360 billion in assets, and is underfunded by an estimated $150 billion, with current assets below 70% of necessary to provide for liabilities. In an effort to reduce this shortfall, at the end of 2016 the board lowered their expected annual rate of return on investments from 7.5% to 7.0%, increasing the costs California cities must pay toward their workers' pensions.