Tesla employees are restricted from forming or joining a union. While this is not official Tesla policy, Tesla’s behavior indicates it does not want its workers to unionize.
For instance, on May 21, 2018, Elon Musk sent this tweet, indicating employees who unionized would lose their stock options: “Nothing stopping Tesla team at our car plant from voting union. Could do so tmrw if they wanted. But why pay union dues & give up stock options for nothing?”
The tweet was just one of Tesla’s many anti-union activities. It has threatened pro-union employees, fired workers for pro-union activities, stopped workers from distributing pro-union flyers to other workers and enforced a dress code to stop employees from wearing clothing with pro-union insignia.