There are many nicknames for the city of Houston, the largest city in Texas and fourth-largest city in the United States. The city's nicknames reflect its geography, economy, multicultural population, and popular culture, including sports and music. They are often used by the media and in popular culture to reference the city.

Houston currently has one official nickname, "Space City", signifying the city's global importance to space exploration and historical role as a prominent center of activity by the National Aeronautics and Space Administration (NASA). Cities adopt official nicknames such as this one to establish a civic identity, promote civic pride, and build community unity. Houston has had other nicknames in the past which have faded in common usage, going as far back as the 1870s.

The city has recently accumulated several unofficial nicknames from among sub-groups within the city, including several whose origins are in the local hip-hop subculture. The most recently added nickname is "The Big Heart", which refers to assistance given by Houston and its citizens to the victims of Hurricane Katrina in 2005 and 2006.