Houston is a multicultural city with a thriving international community supported by the nation’s third largest concentration of consular offices representing 77 nations. Officially, Houston is nicknamed the "Space City" as it is home to NASA's Lyndon B. Johnson Space Center, where Mission Control Center is located. Because of this, "Houston" was the first word spoken on the moon. Many locals, however, prefer to call it the "Bayou City." Other nicknames include "H-Town," "Clutch City," and "Magnolia City."

About 90 languages are frequently spoken in the Houston area. Some neighborhoods with high populations of Vietnamese and Chinese residents have Chinese and Vietnamese street signs in addition to English ones. Houston has two Chinatowns—the original located in Downtown and the recent developed is along Bellaire Boulevard in the southwest area of the city. The city also has a Little Saigon in Midtown and Vietnamese businesses located in the southwest Houston Chinatown.

There are many popular events held in the city celebrating cultures of Houstonians. The largest is the annual Houston Livestock Show and Rodeo that is held over 20 days from late February through early March. The event begins with trail rides that originate from several points throughout the state, all of which convene at Reliant Park for a barbecue cook-off. The rodeo includes typical rodeo events, as well as concert performances from major artists and carnival rides. Another large celebration is the annual Gay Pride Parade held at the end of June to commemorate the struggle for gay liberation, gay rights, gay pride, and the Stonewall riots of the late 1960s in New York City. The event is held along Westheimer Road in the Montrose area—home to many gay establishments, such as restaurants, bars, nightclubs, and coffeehouses. Other events held annually include the Greek festival and Houston International Festival.