A process for producing a graphitic film comprising the steps of (a) mixing graphene platelets with a carbon precursor polymer and a liquid to form a slurry and forming the slurry into a wet film under the influence of an orientation-inducing stress field to align the graphene platelets on a solid substrate; (b) removing the liquid to form a precursor polymer composite film wherein the graphene platelets occupy a weight fraction of 1% to 99%; (c) carbonizing the precursor polymer composite film at a carbonization temperature of at least 300° C. to obtain a carbonized composite film; and (d) thermally treating the carbonized composite film at a final graphitization temperature higher than 1,500° C. to obtain the graphitic film. Preferably, the carbon precursor polymer is selected from the group consisting of polyimide, polyamide, polyoxadiazole, polybenzoxazole, polybenzobisoxazole, polythiazole, polybenzothiazole, polybenzobisthiazole, poly(p-phenylene vinylene), polybenzimidazole, polybenzobisimidazole, and combinations thereof.