Yes, strictly speaking, there may be rare occassions in which a person can sue himself.  The reason is, that people can operate under more than one Legal Capacity.  Example: John Smith is a liquidator or receiver or trustee of a certain company / fund / asset.  John Smith, as a private person, was also damaged by that company / fund / asset.  A lawsuit can be brought by John Smith (the person) against "John Smith, in his capacitor as the trustee of asset X".  Sure enough, the court will probably appoint another entity to "defend" the lawsuit, or the plaintiff will probably request so immediately.  By point to be made, Yes, it is possible that a person may sue himself in Another Legal Capacity.