The growing emphasis on sustainable construction has led to the exploration of alternative materials to partially replace cement in concrete, reducing environmental impact and enhancing performance. This study investigates the effects of partial replacement of cement with rice husk ash (RHA) and bentonite in concrete, focusing on its mechanical properties, durability, and microstructural characteristics. RHA, a byproduct of rice milling, is rich in amorphous silica and exhibits excellent pozzolanic properties, while bentonite, a naturally occurring clay, enhances workability and contributes to improved resistance against permeability and cracking. In this experimental study, cement was partially replaced with RHA at 5%, 10%, and 15% and bentonite at 5%, 10%, and 15% in different mix proportions. The concrete specimens were evaluated for workability, compressive strength, tensile strength, water absorption, and durability characteristics over curing periods of 7, 28, and 56 days. Additionally, durability tests are conducted, such as acid resistance and sorptivity. This study demonstrates the potential of RHA and bentonite as sustainable alternatives to cement in concrete, reducing carbon emissions while enhancing mechanical performance. The findings provide insights into optimizing concrete mix design for sustainable construction applications. Further research is recommended to assess long-term durability and field applications of RHA- and bentonite-based concrete.