Martin Marietta Materials, Inc. is an American company and a supplier of aggregates and heavy building materials, with operations spanning 26 states, Canada and the Caribbean.

In particular, Martin Marietta Materials supplies resources for the construction of roads, sidewalks and foundations.

The present-day materials business is distantly descended from Superior Stone, an aggregates company founded in 1939 in Raleigh, North Carolina.

In 1959, the company was purchased by the American-Marietta Corporation, which merged with the Glenn L. Martin Company a year later to form the Martin Marietta Corporation.

Martin Marietta's Magnesia Specialties business provides a full range of magnesium oxide, magnesium hydroxide and dolomitic lime products.