A credit union, a type of financial institution similar to a commercial bank, is a member-owned nonprofit financial cooperative. Credit unions generally provide services to members similar to retail banks, including deposit accounts, provision of credit, and other financial services. In several African countries, credit unions are commonly referred to as SACCOs (Savings and Credit Co-Operatives).

Worldwide, credit union systems vary significantly in their total assets and average institution asset size, ranging from volunteer operations with a handful of members to institutions with hundreds of thousands of members and assets worth billions of US dollars. In 2018, the number of members in credit unions worldwide was 274 million, with nearly 40 million members having been added since 2016.

Leading up to the financial crisis of 2007–2008, commercial banks engaged in approximately five times more subprime lending relative to credit unions and were two and a half times more likely to fail during the crisis. American credit unions more than doubled lending to small businesses between 2008 and 2016, from $30 billion to $60 billion, while lending to small businesses overall during the same period declined by around $100 billion. In the US, public trust in credit unions stands at 60%, compared to 30% for big banks. Furthermore, small businesses are 80% less likely to be dissatisfied with a credit union than with a big bank.

"Natural-person credit unions" (also called "retail credit unions" or "consumer credit unions") serve individuals, as distinguished from "corporate credit unions", which serve other credit unions.