Subway is an American restaurant franchise that primarily sells submarine sandwiches (subs) and salads. It is owned and operated by Doctor's Associates, Inc. (DAI). Subway is one of the fastest growing franchises in the world with 36,804 restaurants in 100 countries and territories as of May 15, 2012. It is the largest single-brand restaurant chain globally and is the second largest restaurant operator globally after Yum! Brands (over 37,000 locations).

Subway's main operations office is in Milford, Connecticut; five regional centers support Subway's growing international operations. The regional offices for European franchises are located in Amsterdam, Netherlands; the Australia and New Zealand locations are supported from Brisbane, Australia; the Asian locations are supported from offices located in Beirut, Lebanon, Malaysia, Singapore and India and the Latin America support center is in Miami, Florida.

Doctor's Associates, owners of Subway, was founded by Fred DeLuca and Peter Buck in 1966, when they opened the second Subway restaurant in Bridgeport. The name comes from the fact that Buck holds a PhD. Despite their name and Subway's health-conscious image, neither Subway nor Doctor's Associates are affiliated with, nor endorsed by, any medical organizations or doctors.