A graphene (Gr) functionalized silica gel (Gr–SiO₂) sorbent was prepared and used as a new sorbent for solid-phase extraction (SPE) of polycyclic aromatic hydrocarbons (PAHs) including naphthalene, acenaphthylene, fluorene, phenanthrene, fluoranthene, and pyrene. The analytes were separated and detected by high-performance liquid chromatography (HPLC) with a UV detector. Factors affecting the extraction efficiency including the eluent type and its volume, adsorbent amount, sample volume, sample pH and flow rate were optimized. Under the optimized conditions, the present method showed a wide linear range (0.01–600 μg L⁻¹), acceptable repeatability of the extraction (RSDs of 1.7–8.2%, n = 3) and satisfactory detection limits (0.0029–0.052 μg L⁻¹). The recovery studies using this new sorbent were performed by three consecutive extraction steps of water and milk samples at three spiked levels. The average recoveries of the analytes in environmental water and milk samples were 89.0–115.4%, which demonstrated the applicability of the developed method.