Humanized camelid antibodies

The disclosure relates to humanized antibodies derived from the conventional antibody repertoire of species in the family Camelidae. In particular, the disclosure provides an antibody comprising a camelid VH domain and a camelid VL domain of either the lambda light chain class or the kappa light chain class, characterised in that at least one humanising amino acid substitution is present in the VH domain and/or the VL domain.