Can I work as an employee for another company while on a Lithuanian business residence permit?

A residence permit issued for running or participating in a business is linked to that specific activity. It is not a general open work permit, so the rights it gives are connected to the company or lawful activity you applied with.

If you want to take up employment with a different employer, you generally need a permit issued on the appropriate basis, such as a work-based residence permit. Working outside the terms of your permit can put your status at risk, so confirm what you are allowed to do before changing your activity.