The two-photon width Γ γ γ of the η c meson has been measured with the L3 detector at LEP. The η c is studied in the decay modes π + π - π + π - , π + π - K + K - , K 0 s K + /-π , K + K - π 0 , π + π - η, π + π - η', and ρ + ρ - using an integrated luminosity of 140 pb - 1 at s~91 GeV and of 52 pb - 1 at s~183 GeV. The result is Γ γ γ (η c )=6.9+/-1.7stat+/-0.8sys+/-2.0(BR) keV. The Q 2 dependence of the η c cross section is studied for Q 2 <9 GeV 2 . It is found to be better described by a Vector Meson Dominance model form factor with a J-pole than with a ρ-pole. In addition, a signal of 29+/-11 events is observed at the χ c 0 mass. Upper limits for the two-photon widths of the χ c 0 , χ c 2 , and η c ' are also given.