Terminal 21 (Thai: เทอร์มินอล 21) is a chain of mixed-use complexes with 4 locations in Thailand; Asok and Rama III in Bangkok, Korat, and Pattaya.

The number "21" refers to Soi Sukhumvit 21 (Asok Montri Road) where its first branch in Bangkok is located.

Each Terminal 21 complex consists of: a multi-storied retail area with each floors being decorated in the theme of touristic cities around the world, a SF Cinema City movie theatre, and a hotel-and-residence operated by Centre Point Hospitality, a Quality Houses PLC company.

The retail area has a total of 10 stories anchored by an SF Cinema and a Gourmet Market (a division of The Mall Group).

A total of 30 people were killed, including the gunman, making the incident the deadliest mass shooting in Thailand's history.

Each floor is decorated based on touristic cities and locations around the world; The Caribbean, Rome, Paris, Tokyo, London, Istanbul, San Francisco, and Hollywood.