Innovative approaches to prevent bacterial attachment and biofilm growth on membranes are critically needed to avoid decreasing membrane performance due to biofouling. In this study, we propose the fabrication of anti-biofouling thin-film composite membranes functionalized with graphene oxide silver nanocomposites. In our membrane modification strategy, carboxyl groups on the graphene oxide silver nanosheets are covalently bonded to carboxyl groups on the surface of thin-film composite membranes via a crosslinking reaction. Further characterization, such as scanning electron microscopy and Raman spectroscopy, revealed the immobilization of graphene oxide silver nanocomposites on the membrane surface. Graphene oxide silver modified membranes exhibited an 80% inactivation rate against attached Pseudomonas aeruginosa cells. In addition to a static antimicrobial assay, our study also provided insights on the anti-biofouling property of forward osmosis membranes during dynamic operation in a cross-flow test cell. Functionalization with graphene oxide silver nanocomposites resulted in a promising anti-biofouling property without sacrificing the membrane intrinsic transport properties. Our results demonstrated that the use of graphene oxide silver nanocomposites is a feasible and attractive approach for the development of anti-biofouling thin-film composite membranes.