| Abbreviation | Definition |
|---|---|
| CLASPI | Center for Law And Social Policy, Incorporated |
| CLASS | Coalition of Law Abiding Sporting Shooters |
| CLAW | Citizens for Los Angeles Wildlife |
| CLAW | Conservation Laborers Against Wrong |
| CLC | Centre for Liveable Cities |
| CLC | Challenger Learning Community |
| CLC | Chapter Leadership Conference |
| CLEA | Child Labor Education and Action |
| CLEAN | Citizens League For Environmental Action Now |
| CLF | Children's Leukemia Foundation |
| CLFM | Children's Leukemia Foundation of Michigan |
| CLHRF | Canadian Lebanese Human Rights Federation |
| CLINIC | Catholic Legal Immigration Network, Inc. |
| CLIP | CLimate Infrastructure Partnership |
| CLIR | Center for Leadership, Information, and Research |
| CLJI | Center for Law and Justice International |
| CLL | Community Living London (Ontario) |
| CLMS | Concordia Lutheran Mission Society |
| CLNA | Centre de Loisirs Nautiques d'Asnelles |
| CLOVES | Council of Local Organizations for Volunteer Enhancement |