For other meanings of the acronym PUC, see the disambiguation page PUC.

PUC is an abbreviation for the phrase personal unlocking code used in GSM mobile phones. Most mobiles offer the feature of PIN protection. After switching on the phone, the user is requested for security reasons to enter a 4-8 digit PIN enabling the phone's non-emergency calling functions. If the wrong code is typed in more than three times, either the SIM card, the mobile or both become permanently locked.

They can however be reverted to their original unlocked state through entering of a PUC. Mobile users are therefore advised to keep their PUC written down in a safe place separate from the mobile.

PUC is also called PUK, abbreviation for personal unlocking key.