TZ or tz may refer to:

Arts and media:

• The Twilight Zone, an American television anthology series
• Terezi Pyrope, a character from the webcomic Homestuck, frequently called "TZ" by her friend Sollux.
• Tz (newspaper), a German tabloid newspaper from Munich

Places:

• Tappan Zee Bridge, New York, US
• Tappan Zee High School, a public high school in Orangeburg, New York, US
• Tanzania (ISO 3166-1 alpha-2 country code TZ)

Science and technology:

• .tz, the country code top level domain (ccTLD) for Tanzania
• Time zone, a geographic region which uses a common clock time
• Tz database, also called zoneinfo or IANA Time Zone Database, a compilation of information about the world's time zones
• Saxitoxin, a chemical weapon with designation TZ in the US military
• Sony Vaio TZ, a model of personal computer
• Transformation Zone, a term used in cervical cancer therapy, the area of the cervix where dysplasia and abnormal cell growth occur

Other uses:

• -tz, a digraph in linguistics, pronounced /ts/
• ATA Airlines (1973-2008, IATA airline code TZ)
• Scoot (2012-present, IATA airline code TZ until 2017)