The present invention relates to a human or humanized antibody, or an antibody-based binding protein, modified antibody format retaining target binding capacity, antibody derivative or fragment retaining target binding capacity, which targets Receptor tyrosine kinase-like orphan receptor-1 (ROR1). It further relates to bi- or multispecific antibodies, to Immunoligand-Drug Conjugates, to Chimeric Antigen Receptors and to T-cells comprising such Chimeric Antigen Receptors.