The nuclear quadrupole moment of In-115 has been determined by combining the experimental nuclear quadrupole coupling constants and electric field gradients, calculated at the four-component CCSD(T) level of theory, of four indium halides. Our recommended value for the nuclear quadrupole moment of In-115 is 770(8) millibarn. A basis set study at the Dirac-Hartree-Fock level shows a slow convergence of the electric field gradient with respect to higher angular momentum functions.