Nanomaterials play a significant role in adsorption treatment of dye wastewater, but irreversible aggregation of nanoparticles poses a significant problem. In this work, nanomesoporous zinc‐doped silicate (NMSZ) was prepared by an in situ method. To prevent agglomeration, NMSZ was covalently bonded to graphene oxide (GO) sheets to form a nano‐silica/zinc/graphene oxide composite (GO‐NMSZ), aimed at removal of cationic dye methylene blue (MB). For comparison, undoped mesoporous silica (MS) was also synthesized and modified to obtain a silica/graphene oxide composite (GO‐MS). The materials were characterized by powder XRD, SEM, FTIR spectroscopy, TEM, nitrogen sorption, and X‐ray photoelectron spectroscopy (XPS). Preservation of the oxygen‐containing groups of GO in the composites led to higher adsorption capacities. The best GO‐NMSZ composite exhibited an enhanced adsorption capacity of 100.4 mg g−1 for MB compared to those of undoped GO‐MS (80.1 mg g−1) and nongrafted NMSZ (55.7 mg g−1). The nonselective character of GO‐NMSZ is demonstrated by effective adsorption of anionic dye Congo red (127.4 mg g−1) and neutral dye isatin (289.0 mg g−1). The adsorption kinetics, adsorption isotherms, and a thermodynamic study suggested that MB adsorption occurs by chemisorption and is endothermic in nature.