Can an employer legally stop you from working somewhere else?

No matter what’s in your contract, your old employer can’t stop you taking a new job unless it could lose them money. For example if you might: take customers to your new employer when you leave. start a competing business in the same local area.

Do I have to tell employer about second job?

While employees do not have a legal obligation to disclose any other employment to their employers, many employers will restrict you from working elsewhere via a clause in your contract of employment.

Can my employer make me quit my second job?

Absolutely. Not only can they prohibit moonlighting, but they can fire you if they find out you are working a second job if you are violating any written policies or agreements. And if that 2nd job appears to violate the company’s trust or propriety ideas, not only could you get fired, but you could get sued.