Human galectin‐4 is a lectin that is expressed mainly in the gastrointestinal tract and exhibits metastasis‐promoting roles in some cancers. Its tandem‐repeat nature exhibits two distinct carbohydrate recognition domains allowing crosslinking by simultaneous binding to sulfated and non‐sulfated (but not sialylated) glycosphingolipids and glycoproteins, facilitating stabilization of lipid rafts. Critically, galectin‐4 exerts favourable or unfavourable effects depending upon the cancer. Here we report the first X‐ray crystallographic structural information on human galectin‐4, specifically the C‐terminal carbohydrate recognition domain of human (galectin‐4C) in complex with lactose, lactose‐3′‐sulfate, 2′‐fucosyllactose, lacto‐N‐tetraose and lacto‐N‐neotetraose. These structures enable elucidation of galectin‐4C binding fine‐specificity towards sulfated and non‐sulfated lacto‐ and neolacto‐series sphingolipids as well as to human blood group antigens. Analysis of the lactose‐3′‐sulfate complex structure shows that galectin‐4C does not recognize the sulfate group using any specific amino acid, but binds the ligand nonetheless. Complex structures with lacto‐N‐tetraose and lacto‐N‐neotetraose displayed differences in binding interactions exhibited by the non‐reducing‐end galactose. That of lacto‐N‐tetraose points outward from the protein surface whereas that of lacto‐N‐neotetraose interacts directly with the protein. Recognition patterns of human galectin‐4C towards lacto‐ and neolacto‐series glycosphingolipids are similar to those of human galectin‐3; however, detailed scrutiny revealed differences stemming from the extended binding site that offer distinction in ligand profiles of these two galectins. Structural characterization of the complex with 2′‐fucosyllactose, a carbohydrate with similarity to the H antigen, and molecular dynamics studies highlight structural features that allow specific recognition of A and B antigens, whilst a lack of interaction with the 2′‐fucose of blood group antigens was revealed.Database accession codes4YLZ, 4YM0, 4YM1, 4YM2, 4YM3.