The present disclosure relates to humanized antibodies that specifically bind to IL-1R3 or a fragment or derivative thereof or a polypeptide that contains at least a portion of said antibody that is sufficient to confer IL-1R3 binding specificity. Said antibodies inhibit IL-1R3 induced NFkB activity. They also inhibit IL-lalpha, IL-lbeta, IL-33, and/or IL-36 stimulated NFkB activity. The disclosure further relates to use of said humanized antibody in the treatment of an IL-1R3 mediated disease such as cancer. The disclosure finally encompasses a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a therapeutically effective amount of the antibody according to the invention. The pharmaceutical composition can be used in treating a IL-1R3 mediated disease such as cancer.