Hello, I work in Beijing. I teach at a public school which sponsored my visa.
My question is: Is it necessarily illegal for me to work part-time for a different employer? My contract stipulates that I can only work for another employer if the school gives me permission. Do they have that discretion? If so, do they need to take any specific action?
Your best bet is to speak to your employer. What are you planning to do part-time? I know of some English teachers in China who tutor over the weekend, so while it's possible, it doesn't necessarily interfere with their full-time work, and perhaps their schools have given them permission.
It can be illegal if you knowingly breach your contract. Talk to other teachers and your employers, and if you can prove that it won't interfere with your work, you'll most likely be able to go ahead. Have a read of our doing business in China guide for some ideas on approaching the conversation.
Hope this helped, and good luck!