ETR may refer to:
Transportation ElettroTreno, a series of Italian high-speed trains Echigo Tokimeki Railway, a railway operating company in Japan Santa Rosa International Airport, serving Machala, Ecuador Essex Terminal Railway, a short line railroad in Canada
Other First East Turkestan Republic Second East Turkestan Republic Edolo language; ISO language code Emissions Trading Registry Entergy Corporation; NYSE stock symbol Etravirine, a drug used to suppress HIV replication Existential theory of the reals, formal language in computer science Express Toll Route, in Canada; Ontario Highway 407
See also Xetra (trading system); XETR Eastern Test Range, a rocket testing area off of Cape Canaveral; ER or AFETR