RTA may refer to:
Media
- Radio and Television Arts, program at Ryerson University, Toronto, Canada
- Radio Television Afghanistan
- RTA TV, an Afghan channel
- Radiodiffusion Télévision Algérienne
- Real time attack, a game speedrun
Science and technology
- Rapid thermal anneal, in semiconductor fabrication
- Real-time analyzer of audio spectrum
- Renal tubular acidosis, a medical condition
- Restricted to Adults
- Retrospective Think Aloud
- RTA clade of araneomorph spiders
- Retrolateral tibial apophysis, defining the RTA clade
- Rewriting Techniques and Applications, an annual computer-science conference
Transit
United States
- Regional Transportation Authority (Illinois), Chicago
- Regional Transportation Authority (Tennessee), Nashville
- Regional Transportation Agency of Central Maryland
- Regional Transit Authority of Southeast Michigan, Metro Detroit
- Central Puget Sound Regional Transit Authority
- New Orleans Regional Transit Authority
- South Florida Regional Transportation Authority
California
- Riverside Transit Agency, California
- San Luis Obispo Regional Transit Authority, California, US
Ohio
Australia
- Former Roads & Traffic Authority, New South Wales, Australia
United Arab Emirates
Other uses
- Ṛta, a Hindu religious concept
- RTA (Niger), a village
- Ready-to-assemble furniture
- Regional trade agreement
- Residential Tenancies Authority, Queensland, Australia
- Rio Tinto Aluminium
- Royal Thai Army
- Race Team Alliance
- RTA (album), by Rudra