Described are specific-binding therapeutic and/or diagnostic proteins directed against Glypican-3 (GPC3), which proteins include muteins of a lipocalin protein, such as lipocalin 2 (Lcn2 or NGAL). The invention also relates to nucleic acid molecules encoding such proteins and to methods for generation and use of such proteins and nucleic acid molecules. Accordingly, the invention also is directed to pharmaceutical and/or diagnostic compositions comprising such lipocalin proteins, including uses of these proteins.