Fast-a-thon is an SMU Cornerstone Event and by far the largest and most impactful event that the SMU MSA hosts. Its mission is to unite the SMU and Dallas community in raising awareness and funds for a worthy cause. This is done by hundreds of people pledging to fast for an entire day. This raises awareness as well as funds from corporate sponsorships for every person that fasts. That evening those hundreds come together at a formal banquet to break fast together, and learn about and donate towards the cause.

Past charities have included disaster relief, orphan sponsorships, and a local domestic violence shelter. As much as $42,000 has been raised for charity in the past in a single year through Fast-a-thon.