Externalization may refer to:
- Externalization (migration), efforts by countries to prevent migrants reaching their borders
- Externalization (psychology), Freudian psychology, an unconscious defense mechanism by which an individual projects their own internal characteristics onto the outside world.
- Cost externalization, the socioeconomic practice of maximizing profits by off-loading indirect costs and forcing negative effects or externalities to a third party
- Sound externalization, see virtual acoustic space
