TLA is a three-letter abbreviation which can mean several things. Most commonly, it literally means three-letter abbreviation or three-letter acronym, or occasionally three-letter agency.

Other meanings include:

• the Theater of the Living Arts , a concert hall in Philadelphia, Pennsylvania.

In New Zealand, Territorial local authority

At least seven organizations:

• Theater Libraries Association
• Thai Libraries Association in Thailand
• Texas Libraries Association in Texas, USA
• Tennessee Library Association in Tennessee, USA
• Technology Leadership Academy in Missouri, USA
• Texas Locksmiths Association
• Tasmanian Logging Association

Some technical terms:

• Telemetry link adapter
• Telephone line adapter
• Thin layer activation
• Temporal Logic of Actions (see also Temporal logic)

• In U.S. military usage, Travel Lodging Allowance
• Tom Lord's Arch, an implementation of the GNU Arch revision control system