Although infrequent, there are times when an employer makes an overpayment to an employee. Reasons for an overpayment could stem from an accounting error, paying an employee at a rate that is too high or incorrect benefit deductions. Other reasons include terminated employees who receive vacation time before it was earned and sales people whose commission was too large. Regardless of how often or the reason overpaying an employee occurs, the employee is responsible for repaying the money when it is demanded. An error is not an automatic entitlement to keep unearned money.