The present invention provides antibodies that bind to ErbB3 and methods of using same. According to certain embodiments of the invention, the antibodies are fully human antibodies that bind to human ErbB3. In certain embodiments, the antibodies of the present invention block the interaction of ErbB3 with an ErbB3 ligand such as neuregulin 1. The antibodies of the invention are useful for the treatment of various cancers.