ECOTEC (Emissions Control Optimisation TEChnology) is a General Motors trademark that refers to a series of emissions technologies that were implemented throughout a range of GM engines.
- Ecotec Family 1 and Family 0 - straight-4 DOHC engines produced by Opel Powertrain and GM Daewoo
- Ecotec Family II - Straight-4 all-aluminium DOHC engines produced by GM Powertrain and Opel Powertrain
- Ecotec V6 - a version of he 3800 V6 engine, Series II and III, produced by Holden Engine Company (replaced in production by Alloytec)
- CDTI Ecotec - common rail diesel engines for Opel cars, produced by Fiat (MultiJet) and GM Daewoo (with VM Motori)
- DTI Ecotec - diesel engines for use in Opel cars, produced by Isuzu (Circle L)