Drywall (also known as plasterboard, wallboard, sheet rock, gypsum board, or gypsum panel) is a panel made of calcium sulfate dihydrate (gypsum), with or without additives, typically extruded between thick sheets of facer and backer paper, used in the construction of interior walls and ceilings. The plaster is mixed with fiber (typically paper, fiberglass, asbestos, or a combination of these materials), plasticizer, foaming agent, and various additives that can reduce mildew, flammability, and water absorption.

In the mid-20th century, drywall construction became prevalent in North America as a time and labor saving alternative to traditional lath and plaster.

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