California employees rely on their jobs in order to get income. Without that income they may not be able to support their families and meet all their financial obligations. For this reason, when someone is terminated from their job, they are usually very upset. In some cases, the termination may be expected; however, other times the termination comes out of the blue. This can lead some people to question if a person can be terminated from a job in California without notice.
In short, yes, a person can be terminated from the person's job without notice -- in some circumstances. Generally, in California, employees are at will employees. This means that employers retain the right to fire a person for any reason, at any time. This means that people can be terminated even for the most trivial reasons or at a moment's notice.
However, there are some exceptions to this general rule. First, if the employer says that you can only be fired for cause, then the employer must have a reason for firing you. In some situations, even causal comments about needing cause to terminate you can be enough to hold an employee to this exception. Additionally, if you have an employment contract with your employer, then you can only be fired for the reasons outlined in the contract.
Furthermore, employers cannot, even with an at-will relationship, terminate someone for discriminatory reasons. This means that your race, religion, gender, sexual orientation, age or other similar factor cannot be used as a reason to fire you. An employer is also prohibited by employment laws from firing you in retaliation for certain conduct.
When a person is terminated, that person should seek specific legal advice -- which this post cannot provide -- if the person thinks that the termination was wrongful. Even when a person is an at-will employee, the employee has many employee rights that must be upheld.
Source: Findlaw.com, "At-Will Employee FAQ's," accessed Jan. 25, 2015