In the title trinuclear cobalt-terbium complex, [Co(2)Tb(C(4)H(5)O(2))(6)(NO(3))(C(10)H(8)N(2))(2)], the central Tb(III) and each of the Co(II) ions are bridged by three carboxyl-ate groups of the methacrylate anions. The Tb(III) cation is coordinated by six O atoms from six methacrylate anions and two O atoms from a chelating nitrate anion in a distorted square-anti-prismatic geometry. Each Co(II) ion is coordinated by three O atoms from three methyl-acrylate anions and two N atoms of a 2,2'-bypiridine ligand in a distorted square-pyramidal geometry. In the crystal structure, π-π stacking between the pyridine rings [centroid-centroid distances = 3.682 (8) and 3.760 (8) Å] is observed and weak inter-molecular C-H⋯O hydrogen bonding is also present.