In the crystal of the title compound, C(7)H(13)IO(5), the molecules are linked by O-H⋯O hydrogen bonds, which build linkages around one screw axis of the cell. These C(5) and C(6) packing motifs expand to R(2) (2)(10) and C(2) (2)(11) motifs and are similar to those found for closely related compounds. The galactoside ring has a (1)C(4) chair conformation.