As a general rule of thumb - no. But there are exceptions. What type of tile do you have now?
Ok, what do you want to put on top? You can't put ceramic or stone over this existing tile as it will fail in the short term. Plus you will have an elevation change which will create a tripping hazard. And your doors would have to be cut down too. I would remove what you have then install your desired flooring.
Is your old tile perfectly flat, no cracks or loose tile? Do you have the extra height needed?
Tile is rather fragile until it is bonded to a stable substrate (such as backer board) with thin set. Tile over tile is a recipe for disaster and a waste of time and money.