A chamber of commerce is a voluntary association whose membership is comprised of companies, civic leaders, and individual business people. Its members seek to promote the interests of business, typically in a broad-based way. Chambers of commerce exist on municipal, state, regional, national, and even international levels. Today, chambers of commerce—sometimes called boards of trade or commercial associations—can be found in most of the world's industrialized countries.

The first chambers of commerce were founded in 1599 in continental Europe . The world's oldest English-speaking Chamber of Commerce is that of Glasgow, Scotland, that was established in 1783.

Membership in an individual Chamber in an area can range from a few dozen to well over 300,000. Some Chamber organizations in China report even larger membership numbers. Businesses which belong to a Chamber of Commerce can range from a single city or town Chamber, to a county Chamber, to a Regional Chamber of Commerce to billion-dollar corporations .

The chambers do not operate in the same manner as the Better Business Bureau in that, while the BBB has the authority to bind its members under a formal operations doctrine (and, thus, can remove them if complaints arise regarding their services), the local chamber membership is strictly voluntary.

Chambers of commerce also can include economic development corporations or groups (though the latter often is a formal branch of a local government, the groups work together and may in some cases share office facilities) as well as tourism and visitors bureaus.

Some chambers have joined state, national, and even international bodies (such as EUROCHAMBRES, the International Chamber of Commerce (ICC) and Worldchambers). In the majority of countries, the use of the term "chamber of commerce" is regulated by federal law. Currently, there are about 13,000 Chambers registered in the official Worldchambers Network registry, and the Chamber of Commerce network is the largest business network globally.

At the national level, chambers of commerce function as a unified voice for their affiliates. The U.S. Chamber of Commerce, for example, counts individual companies, affiliate chambers of commerce, and trade and professional associations among its members. Through them, it represents more than three million business organizations and individuals. Founded as a national federation in 1912 and headquartered in Washington, D.C., the national chamber was instrumental in persuading the federal government to institute a national budget and in gaining passage of the Federal Reserve Act. Its chief aims are to: stop perceived over regulation; push down business taxes; improve labor relations; increase production, develop new markets; provide more jobs; raise educational levels; build better cities; and keep organized business strong and increasingly effective.