The teleprinter, also called a teletypewriter, is a typewriter-printer that sends messages over telegraph or other data communication lines to a similar receiving printer, which automatically prints the message. The transmitter inputs the message on a typewriter-like keyboard, which converts each keystroke to a coded electrical impulse and sends it to the receiver, which interprets the impulses to reproduce the original keystrokes. The teleprinter was first developed by Frederick G. Creed (1871-1957), a Nova Scotian who was inspired by his work as a telegrapher to find a way to send printed messages without using Morse code. Creed immigrated to Scotland in 1897, where he experimented with his typewriter (which he ever after kept with him) to produce the first teleprinter. Although the British Post Office bought a dozen of Creed's machines in 1902, their use did not catch on.

In the United States, Charles L. Krumm designed the prototype of the modern teleprinter in 1907. A refined version of this machine was widely marketed in the United States in the 1920s, where it was most often referred to by its American Telephone and Telegraph trade name, Teletype. A similar machine was sold at the same time in Germany by Siemens-Halske. Both used a code originally devised by Emile Baudot (1845-1903) for his multiplex telegraph and adapted by Donald Murray of New Zealand in 1903 for his multiplex page-form-telegram system. Other teleprinters were developed that used a different keyboard code, the American Standard Code for Information Interchange (ASCII). Commercial teleprinter exchange services, called TRX and Telex, were developed in the 1930s. News wire services became heavy users of teleprinter communications.

Early teletypewriters printed on strips of gummed tape, which was cut to length and pasted onto telegram forms. Later machines printed messages in page form. At first, teleprinters produced up to 500 characters per minute. By the mid-1960s these machines had upped their output to 900 words per minute. Beginning in the 1980s, teleprinters were being replaced by direct transmissions from communication satellites to computers, electronic computer delivery and fax machines.