Due to the economic and environmental cost of producing cement for concrete, research into the use of alternative materials such as geopolymers for the partial replacement of cement has become popular. In an attempt to understand the effect of such replacement on the shielding behavior of concrete, this study evaluated and analyzed the gamma-ray interaction parameters of fly ash- and rice husk ash-based geopolymers (G-RHA-F1, G-RHA-F2, G-RHA-F3, and G-RHA-F4). The mass attenuation coefficient (μρ), mass energy absorption coefficient (μenρ), effective atomic number (Zeff), specific gamma-ray dose constant (Г), dose rate (Dr), and photon buildup factors (BFs) were computed for photon energies within 15,000 eV and 15,000 keV. The evaluated parameters showed differences in value for the materials. For G-RHA-F1, G-RHA-F2, G-RHA-F3, and G-RHA-F4, μρ values are within the range 0.0208–6.5169 cm2/g, 0.0208–6.3631 cm2/g, 0.0209–6.70611 cm2/g, and 0.0208–6.2149 cm2/g, respectively. The corresponding ranges of are 0.0155–5.9433 cm2/g, 0.0155–5.7934 cm2/g, 0.0156–6.4016 cm2/g, and 0.0155–5.6775 cm2/g, accordingly. Fly ash slightly improved the gamma photon absorption capacity of the geopolymers, especially at the low energies. The investigated geopolymers have relatively higher photon absorption cross-sections relative to some existing polymers and shielding glasses. They could therefore be used to construct effective concrete shields.