An employee may work for more than one employer simultaneously. As a general rule, employers cannot prohibit this. 

However, this does not mean that employers cannot react to parallel employment. They can always evaluate whether an employee’s additional work affects their ability to perform their primary job effectively. The employee should turn up for work ready to perform their job, which implies an appropriate psychological and physical (rest) level. If working a second job is leaving the employee tired, prone to making mistakes, coming to work late, etc., then the employer may terminate the employment contract with the employee, citing the improper performance of the employee's duties. The second employment will, in that case, only be the background of the employee's attitude. 

Furthermore, the employer can react if employment with a second employer creates a conflict of interest that cannot be avoided. The employer may then call upon the employee to remove the conflict of interest by terminating the employment contract with the second employer. If the employee does not comply, then the employer may even terminate the employee's contract.

Employers concerned about potential conflicts of interest should consider implementing non-compete agreements during the employment relationship. These agreements prohibit employees from working with all competitors and provide an additional layer of protection for the employer’s business interests. Importantly, such agreements do not incur extra costs and can be a valuable tool in managing concurrent employment risks.  However, certain professions may have specific regulations governing concurrent employment, for example, drivers.

Find more in the PRO HR March 2025.