EPR measurements have been made at room temperature on Tl2ZnF4 crystals dopedwith Gd3+ andco-doped with Gd3+and Li+.For crystals doped only with Gd3+,a spectrum with tetragonal symmetry (A centre) is observed. For co-dopedcrystals new spectra with tetragonal (B centre) and monoclinic (Ccentre) symmetries are observed in place of the spectrum of the Acentre. The A centre is identified as the substitutional Gd3+ ion at aZn2+site in six-fold coordination without any local charge compensation in its immediateneighbourhood. On the basis of spin Hamiltonian separation analysis, the separated parameterb2a(1) for the C centrehas a value close to the b20parameter for the B centre. The B and C centres in co-doped crystals are ascribed to a Gd3+ ion substitutedfor a Tl+site in nine-fold coordination, where the divalent excess positive charge on Gd3+ is compensatedby a Li+ ionat the Zn2+site along the caxis. For the C centre, another association with a Li+ ion is found at thenearest Zn2+site along the [111] direction. The other separated parameterb2a(2)for the C centre has an opposite sign and six times the magnitude ofb20 for theGd3+centre with trigonal symmetry along the [111] direction in RbCaF3. Thelarge magnitude negative value may be due to the deviation of the ligands toward the Li+ ion at the nearestZn2+site.