Silver nanoparticle-decorated graphene oxide (AgNPs–TWEEN–GO) was synthesized and used for fabricating a non-enzymatic H₂O₂ sensor. The nanocomposites were synthesized for the first time through a facile method using TWEEN 80 as the modifier for GO as well as the reducing and stabilizing agent for AgNPs. Transmission electron microscopy observations revealed that large numbers of AgNPs were distributed on the surface of the GO and the electrochemical investigations indicated that the nanocomposites possessed an excellent performance for the detection of H₂O₂. The linear range was estimated to be from 0.02 mM to 23.1 mM H₂O₂ with a low detection limit of 8.7 μM (S/N = 3) and a response time of 3 s.