The present invention provides antibodies that specifically bind to EGFRvIII (Epidermal Growth Factor Receptor Variant III). The invention further provides bispecific antibodies that bind to EGFRvIII and another antigen (e.g., CD3) as well as antibody conjugates (e.g., antibody-drug-conjugates). The invention further relates to antibody encoding nucleic acids, and methods of obtaining such antibodies (monospecific and bispecific) and antibody conjugates. The invention further relates to therapeutic methods for use of these antibodies and antibody conjugates for the treatment of EGFRvIII-mediated pathologies, including cancer such as glioblastoma.