Traditional piezoelectric materials are expensive and environmentally unsustainable, limiting their adoption in energy-harvesting building applications. This study proposes an eco-friendly approach for developing a waste-derived hydroxyapatite (HAP)-reinforced piezoelectric geopolymer hybrid composite using eggshell waste and fly ash. Eggshell-derived calcium carbonate was converted into hydroxyapatite through a controlled precipitation process, and the synthesized HAP was characterized for structural purity, morphology, and dielectric properties. Geopolymer composite specimens of 50 mm cubic geometry were fabricated by incorporating 15 wt% HAP, 25 wt% ZnO, and 10 wt% TiO₂ into a Class F fly ash-based geopolymer matrix and cured at 70 °C for 48 h. Under uniaxial compressive loading, the hybrid composite generated a maximum piezoelectric voltage output of 0.149 V at a compressive stress of 22.12 MPa, while maintaining a compressive strength suitable for non-structural construction applications. Microstructural analysis confirmed uniform dispersion of HAP within the geopolymer matrix, contributing to enhanced interfacial polarization and dielectric response. The results demonstrate that waste-derived HAP can function as an effective, lead-free piezoelectric phase, enabling the development of sustainable, energy-responsive geopolymer materials for self-sensing and energy-harvesting applications.