South by Southwest (SXSW) is a set of film, interactive, and music festivals and conferences that take place every spring (usually in March) in Austin, Texas, United States. It began in 1987, and has continued to grow in size every year. In 2011, the conference lasted for 10 days, with SXSW Interactive lasting for five, Music for six, and Film running concurrently for nine days.

South by Southwest is run by a company, called SXSW Inc., that plans and executes conferences, trade shows, festivals and other events. In addition to the three main South by Southwest festivals, the company runs three other conferences, two in Austin: SXSWedu, a conference on educational innovation, and SXSW Eco, an environmental conference; and one in Las Vegas: SXSW V2V, a conference focused on innovative startups.