Runner's World is a global magazine and website for runners of all abilities. It has additionally developed experiential formats, including a digital membership program, called Runner's World+. It is published by Hearst in Easton, Pennsylvania and was formerly published by Rodale, Inc. Outside the United States, the magazine is published in France, Germany, Italy, Norway, South Africa, Spain, Sweden, the United Kingdom, and the Netherlands.

Runner's World was originally launched in 1966 by Bob Anderson as a mimeographed newsletter Distance Running News, and Anderson published it by himself for several years from his home in Manhattan, Kansas. Runner and writer Hal Higdon had been writing for the magazine since its second edition.

In 1969, Anderson changed the name of the magazine to Runner's World. He brought on Joe Henderson as chief editor and moved the editorial offices, now named World Publications, to Mountain View, California. Runner's World thrived during the 1970s "running boom", even in the face of competition from the New York City–based magazine, The Runner.

In May of 1970 Doris Brown became the first woman to be on the cover page of the magazine, marking an important milestone for the magazine. Additionally, in 1973 the magazine began to be printed in color. Later on, October of 1987 Runner's World implemented Miles, the little running man as the apostrophe in the Runner's World title. The most recent logo change happened in October 2014, which still remains the current logo in 2025.

In the early 1980s, Bob Anderson sold a good portion of his publications, including Runner's World. Some of Anderson's books went out of print while others were distributed by Macmillan Publishing. Robert Rodale of Rodale, Inc., purchased Runner's World in 1985 and the editorial offices moved to Rodale's base in Emmaus, Pennsylvania. Joe Henderson did not move to Emmaus, and stepped down as editor, though he remained associated with the magazine until 2003. Random House bought the running log, which was published under the Runner's World name for decades after the sale.

In 1986, Rodale bought The Runner, and merged the two magazines, keeping the Runner's World name and some writers, including Amby Burfoot who became the editor (a post he held until 2003).

Runner's World remained strong through the so-called "second running boom" in the late 1990s. In 2004, the magazine had a full redesign. Since then, the magazine has won several awards including being ranked No. 1 on Adweek's Hot List, No. 6 on Advertising Age's "A-List"; been recognized for having the "Creative Team of the Year", and most notably has been nominated three times for National Magazine Awards.

In February 2007, Rodale acquired Running Times magazine and website and combined both brands in 2015.