A payphone (alternative spelling: pay phone) is typically a coin-operated public telephone, often located in a telephone booth or in high-traffic outdoor areas, with prepayment by inserting money (usually coins) or by billing a credit or debit card, or a telephone card. Prepaid calling cards also facilitate establishing a call by first calling the provided toll-free telephone number, entering the card account number and PIN, then the desired telephone number. An equipment usage fee may be charged as additional units, minutes or tariff fee to the collect/third-party, debit, credit, telephone or prepaid calling card when used at payphones. By agreement with the landlord, either the phone company pays rent for the location and keeps the revenue, or the landlord pays rent for the phone and shares the revenue.

Before the ubiquity of mobile phones, payphones were often found in public places to contribute to the notion of universal access to basic communication services. In the late 1920s, the cost of a payphone call in the United States was two cents. In the 1930s, calls were five cents. Early in the 21st century as payphones became rare, the price of a call was fifty cents. One thesis, written as early as 2003, recognized this as a digital divide problem.

In the 20th century, payphones in some countries, such as Spain, used token coins, available for sale at a local retailer, to activate payphones, instead of legal tender coins. In some cases, these were upgraded to use magnetic cards or credit card readers over the years.

Payphones were once ubiquitous worldwide, but their prevalence has declined significantly in the 21st century due to the increasing availability of mobile phones. New York City, which once had 30,000, removed its last public payphone in 2022.