Mechanical robustness and durability are crucial for anion exchange membranes to guarantee the longevity and consistent performance of AEM water electrolysis (AEMWE) systems. In this study, a composite membrane based on the quaternized poly(p‐phenylene oxide) (QPPO)/polytetrafluoroethylene (PTFE) was developed. This membrane was fabricated by enhancing the QPPO‐based AEM through a pore‐filling technique within a porous PTFE structure. The tensile strength of the composite membrane was increased significantly from 16.5 to 31 MPa. The conductivity of the composite membrane was 6.25 mScm−1 lower than 30 mScm−1 of the QPPO‐based membrane at 20°C, resulting from the low volume fraction of QPPO in the composite membrane. At 40% RH, the net change mass of the composite membrane is 1.59%, much lower than that of QPPO‐based membrane (10.98%) at 40°C. The composite membrane demonstrated a significantly increased lifetime in the working electrolyzer (>200 h) compared with an otherwise identical electrolyzer assembled with a QPPO‐based membrane (50 h).