ECU may refer to:
Currencies
- European Currency Unit, precursor to the euro
- Écu, French coins of the 13th–19th centuries
Technology
- Electronic control unit
- Engine control unit
Universities
- East Carolina University, in Greenville, North Carolina, United States
- East Central University, in Ada, Oklahoma, United States
- Edith Cowan University, in Perth, Australia
- Emily Carr University of Art and Design, in Vancouver, Canada
Other uses
- Eastman Credit Union, an American credit union
- ÉCU The European Independent Film Festival
- Ecuador, UNDP country code
- Eighth Creative Union of MEPhI, a Russian theatre company
- End Citizens United, a PAC working to get big money out of politics
- European Chess Union
- Evidence Control Unit
- Extensor carpi ulnaris muscle
- Extreme close-up