Which? is a United Kingdom brand name that promotes informed consumer choice in the purchase of goods and services by testing products, highlighting inferior products or services, raising awareness of consumer rights, and offering independent advice. The brand name is used by the Consumers' Association, a registered charity and company limited by guarantee that owns several businesses, including Which? Financial Services Limited, Which? Legal Limited and Which? Limited, which publishes the Which? Papers.

Consumer organizations are advocacy groups that seek to protect people from corporate abuse like unsafe products, predatory lending, false advertising, astroturfing and pollution.