St. Mary's Medical Center (SMMC) is a hospital in Huntington, West Virginia, USA. With 393 beds, it is the second-largest medical facility in the tri-state region. West Virginia, Ohio, and Kentucky meet following UK King's Daughters in Ashland, Kentucky which has 465 beds. The medical center is the largest private employer in Cabell County with over 2600 employees. SMMC has centers in cardiac care, cancer treatment, an emergency department with a Level II Trauma Center, and neuroscience.

As a teaching facility associated with the Marshall University Joan C. Edwards School of Medicine, St. Mary's trains medical residents in several specialties. The hospital campus is home to the St. Mary's School of Nursing, the St. Mary's School of Radiologic Technology, and the St. Mary's School of Respiratory Care. All three programs are associated with Marshall University. It is also the home to the Marshall University Physical Therapy program, which began in 2013.

In 2015, the hospital further affiliated with UK HealthCare's (University of Kentucky) Markey Cancer Center.

On November 6, 1924, the Sisters of the Pallottine Missionary Society opened St. Mary's Hospital. In August 2002, the hospital was renamed St. Mary's Medical Center. On July 9, 2012, St. Mary's opened a 24-hour-a-day, 7-day-a-week 12-bed Emergency Room in Ironton, Ohio. It contains acute and trauma rooms, imaging and lab services, and specialty doctors will rotate between the Ironton Campus and Huntington Campus.

In 2014, St. Mary's signed a definitive merger agreement with Cabell Huntington Hospital, forming Mountain Health Network (now known as Marshall Health Network).