The nuclear-recoil effect on the g factor of the ground state of highly charged B-like ions is studied to first order in the electron-to-nucleus mass ratio m/M. The leading one-electron and two-electron recoil contributions are calculated nonperturbatively in the parameter αZ within the rigorous QED formalism. The interelectronic-interaction correction to the nuclear-recoil effect is evaluated in the Breit approximation by means of perturbation theory to the first order in 1/Z. The higher-order interelectronic-interaction corrections are taken into account partially by performing the calculations with the effective screening potential. The results obtained represent an up-to-date treatment of the nuclear-recoil effect on the g factor of highly charged B-like ions in the range Z=20-92.