The modulation instability of a circularly polarized laser pulse in a magnetized non-Maxwellian plasma is investigated. Based on a relativistic fluid model, the nonlinear interaction of an intense circularly polarized laser beam with a non-Maxwellian magnetized plasma is described. Nonlinear dispersion relation and growth rate of the instability for left- and right-hand polarizations are derived. The effect of temperature, external magnetic field, value of Kappa and state of polarization on the growth rate are analyzed. It is shown that the growth rate increases with increase in the magnetic field for the right-hand polarization and inversely it decreases for the left-hand one. Also it is observed that existence of super-thermal particles causes the decrease in the growth.