Cost-efficient, easy processing antistatic PEEK/Expanded graphite (EG) nanocomposites were prepared via twin-screw extrusion and injection moulding. 0.5,1,3 vol% of unfunctionalized EG with a diameter of 600 μm were melt mixed with PEEK and the rheological, electrical, and thermal properties of the nanocomposites were investigated. The storage modulus (G^') of the nanocomposite containing 1 vol% EG was almost independent of the angular frequency at low frequencies. Zero-shear viscosity exhibited an earlier shear thinning behaviour at low shear rates for EG loadings of 1 vol%. However, it did not increase much with the addition of EG in comparison with other nanofillers such as carbon nanotube. Also, with an increase of the EG loading to 3 vol%, DC electrical conductivity exhibited an abrupt increase to 2e-6 S/m which is in the required range of electrical conductivity for antistatic materials. Therefore, the rheological and electrical percolation thresholds of the PEEK/EG nanocomposites occur at the EG loadings of 1 and 3 vol%. The PEEK crystallinity in the composite containing 3 vol% EG was enhanced by 12%.