The cell wall of a plant is the thick outer most protective layer external to the plasma membrane. The cell wall of plants is composed of cellulose fibers embedded in a polysaccharide-protein matrix. Sometimes there can be two layers of the cell wall. The first one, present in all plants, is called the primary wall which is thin and flexible. The secondary wall is present in some plants and it is stronger and more rigid which adds protection and support.

The cell wall is one of the features of plant cells that distinguishes them from animal cells. The cell wall protects the plant cell, maintains its shape, and prevents excessive uptake of water.