Cancer is a major health concern causing death worldwide, demanding novel methods for its detection and treatment. Antibody targeted nanomaterials have surfaced as a cutting-edge method with the potential to revolutionize the field of oncology. Antibodies are specialized proteins designed to attach precisely to antigens, which are specific molecules found on the exterior of cells, given that cancer cells frequently exhibit distinct antigens, they become particularly attractive targets for nanobiomaterials combined with antibodies. This concordant fusion holds the prospect of achieving enhanced accuracy and effectiveness in the diagnosis and treatment of cancer. In recent times, nanotechnology-based immunotherapeutic treatments have been employed in various cancer cases with the aim of diminishing the aggressiveness of cancer cells while preserving the well-being of neighboring healthy cells at the specific tumor location. In this chapter, we outline the foundational principles of nanobiomaterials, antibodies, with their precise targeting capabilities along with antibody-nanobiomaterial conjugation, enhanced drug delivery, advanced imaging, theranostics, and novel cancer therapy. Further, safety, ethical, regulatory considerations, and we conclude by discussing future directions, underscoring the potential for personalized cancer care. This chapter offers a comprehensive overview of how antibody-targeted nanobiomaterials are poised to reshape cancer diagnosis and therapy, ushering in an era of heightened precision and effectiveness in the fight against cancer.