If I quit or am terminated, what happens if the employer withholds my last paycheck in California?

You must receive payment in full for the time you worked. In some states, your employer must also pay you for any accrued vacation days. 

When you receive your last paycheck, it depends on your state. Some states require the last paycheck to be delivered immediately, other states require the issuance of the paycheck within a few days, and other states allow up to 21 days. 

A month, however, to receive your last paycheck is too long. If you believe your employer has wrongfully withheld your last paycheck, you should contact your state's labor department or even the federal labor department. An attorney can assist you with this as well.