The Tb[Formula: see text]Ce[Formula: see text]Mn6Sn6 compounds with [Formula: see text] crystallize in the hexagonal HfFe6Ge6-type structure (space group [Formula: see text]). The cerium (Ce) substitution for Tb increases the magnetization while reduces the Curie and spin-orientation temperatures. The hard magnetic properties are enhanced by the Ce substitution, e.g., from a coercivity of [Formula: see text] kOe for TbMn6Sn6 to [Formula: see text] kOe for the Ce-substituted compounds with [Formula: see text] at 5 K. The role of Ce substitution in the magnetocrystalline anisotropy is discussed based on the single-ion anisotropy model. The substitution of Ce for critical rare-earth atoms provides an opportunity of improving hard magnetic properties of the rare-earth-based intermetallics.