The investigation of high-internal-phase Pickering emulsions (HIPPEs) by food scientists has been motivated by their remarkable structural stability, which has significant implications for the development of innovative food textures and the delivery of lipophilic components. The development of sustainable food-grade stabilizers has proven to be a persistent challenge in the context of the HIPPE system in the food industry. In this study,

Agaricus bisporus

aggregates (AAs), derived from the wastes through preprocessing and alkali isolation, were evaluated for their potential as a natural stabilizer for HIPPEs. Stable HIPPEs were prepared with AAs in a range of 1.00–1.50%w/w. In contrast, HIPPEs were not prepared with insufficient (0.75%w/w) and excessive (1.75%w/w) AAs, resulting from incomplete and overload interfacial coverage, respectively. In the stably prepared HIPPEs, it was confirmed that the uniform size distribution of oil droplets was attributable to effective AA adsorption at the oil-water interface. Furthermore, it was observed that all stable HIPPE formulations exhibited gel-like behavior, with G′ consistently exceeding G″. It is noteworthy that the HIPPE prepared with 1.25%w/w AA exhibited the most pronounced viscoelasticity and thermal resistance (25–90°C), indicative of a robust interfacial network. These findings demonstrate the viability of AAs as a sustainable HIPPE stabilizer and provide insights into the rational design of stable food structures