Optimistic Concurrency Control (OCC) is a database management technique that allows multiple transactions to occur simultaneously without locking resources. It assumes that conflicts between transactions are rare, so it lets them execute without restrictions. At the end of each transaction, the system checks for conflicts before committing changes. If a conflict is detected, the transaction is rolled back, and the user may need to retry. This approach can improve performance in environments with low contention, as it reduces the overhead associated with locking mechanisms. However, it may lead to increased retries in high-contention scenarios.