Alkali-silica reactions (ASR), a chemical reaction between the alkali and hydroxyl ions produced by Portland cement hydration and certain types of silica present in the aggregate, causes extensive cracking and strength loss. Steel fibers are used to control crack formation and prevent damage caused by ASR as the fibers are more effective in interacting with small cracks. Steel fibers also control cracking associated with the volumetric expansion of the alkali silica (AS) gel. The mortar specimens without fibers exhibit excessive cracking and reduction in compressive and flexural strength due to ASR. The expansion associated with ASR is reduced with increasing fiber volume fraction. The lack of crack formation prevents the AS gel from leaving the reactive aggregates and hence confines it to reaction sites. Cracking associated with ASR is successfully controlled and minimized with steel fibers at fiber volumes beyond 1%.