There is disclosed compositions and methods relating to or derived from anti-ErbB3 antibodies. More specifically, there is disclosed fully human antibodies that bind ErbB3, ErbB3-binding fragments and derivatives of such antibodies, and ErbB3-binding polypeptides comprising such fragments. Further still, there is disclosed nucleic acids encoding such antibodies, antibody fragments and derivatives and polypeptides, cells comprising such polynucleotides, methods of making such antibodies, antibody fragments and derivatives and polypeptides, and methods of using such antibodies, antibody fragments and derivatives and polypeptides, including methods of treating or diagnosing subjects having ErbB3 related disorders or conditions, including various inflammatory disorders and various cancers.