Durability and sustainability are essential serviceability concerns for alkali-activated composites used in construction. Incorporating inorganic fibers both metal and nonmetal one in alkali-activated materials is beneficial, considering their availability, are more resistant, more rigid, have an higher melting point, and are more heat resistant than traditional fibers. The durability of natural fiber-reinforced alkali-activated composites is influenced by several factors, including type and content of fiber, dispersion and size of fiber, fiber modification, fiber moisture content, fiber alkaline degradation, and fiber mineralization. Besides, this chapter indicates the durability of inorganic fiber-reinforced alkali-activated composites in terms of crack resistance and toughness, high-temperature resistance, wet/dry cycles, freeze-thaw cycles, chemical resistance, and carbonation resistance.