<p>The inimitable and terrific attributes of graphene have drawn attention to this 2D carbon allotrope for a vast range of applications in science. One of the tools to achieve the integration of planar and non-planar circuits is substrate integrated waveguide technology. The reason is the use of the planar manufacturing procedure. This work offers a fourth-order quasi-elliptic graphene-based substrate integrated waveguide filter. The designed filter is wideband. Other essential features of this filter include frequency reconfigurability and miniaturization. In summary, the innovation of a graphene-based reconfigurable fourth-order quasi-elliptic SIW filter in the THz band combines advanced materials science with cutting-edge filter design, resulting in a versatile and high-performance component suitable for next-generation THz systems. The three transmission zeroes (TZs) of this quasi-elliptic fourth-order graphene-based substrate integrated waveguide filter are located at 10.1 THz, 13.3 THz, and 15 THz. The poles of this quasi-elliptic fourth-order graphene-based substrate integrated waveguide filter are located in these four positions: 10.4 THz, 11.7 THz, 12.1 THz, and 12.5 THz, respectively. The central frequency (f₀) of the filter is located at 11.6 THz. The perfect bandwidth of the quasi-elliptic fourth-order graphene-based substrate integrated waveguide filter is estimated at about 2 THz. It’s placed on a single-layer substrate from silicon dioxide (SiO₂) material. The results of this structure exhibit a suitable selectivity, and an insertion loss of 1.8 dB. Fractional bandwidth is estimated at about 17.24%.</p>