A correction for the quadrupole-quadrupole interaction energy is applied to the quadrupole moment of CO₂ measured from the far infrared collision-induced spectrum. The resultant values for the quadrupole moment of CO₂, obtained using two different theoretical equations, are (4.6+or-0.3)*10^-20 esu cm² and (4.3+or-0.4)*10^-20 esu cm² respectively ((4.6+or-0.3)*10^-31 C m² and (4.3+or-0.4)*10^-31 C m² in SI units).