The present invention is directed to B7-H3×CD3 bispecific monovalent diabodies, and particularly, to B7-H3×CD3 bispecific monovalent Fc diabodies, that are capable of simultaneous binding to B7-H3 and CD3. The invention is also directed to pharmaceutical compositions that contain such bispecific monovalent Fc diabodies. The invention is additionally directed to methods for the use of such diabodies in the treatment of cancer and other diseases and conditions.