| ACE | Association Charentaise pour l'Espéranto | In French | → Associations |
| ACE | Action Communautaire pour l'Environnement | In French | → Nature |
| ACE | Advisory Committee on the Environment | In English | → Nature → Environment, environmental sciences |
| ACE | Acceptance Checkout Equipment | In English | |
| ACE | Attitude Control Electronics | In English | → Electronics → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| ACE | Automatic Checkout Equipment | In English | |
| ACE | Angiotensin Converting Enzyme | In English | → Enzymes → Cardiology |
| ACE | Asean Centre for Energy | In English | → Energy economics |
| ACE | Association for the Conservation of Energy | In English | → Energy economics |
| ACE | Association des Cinémathèques Européennes (www.acefilm.de) | In French | → Associations → Cinema, movies |
| ACE | American Cinema Editors (www.ace-filmeditors.org) | In English | → Organizations and associations → Cinema, movies |