A green wall is a wall partially or completely covered with greenery that includes a growing medium, such as soil, water or a substrate. Most green walls include an integrated water delivery system. A green wall is also known as a living wall or vertical garden. It provides insulation to keep the building's inside temperature consistent.

Green walls are different from green facades. Green walls have growing media supported on the face of the wall while green facades have soil only at the base of the wall and support climbing plants on the face of the wall to create the green.

Green walls may be indoors or outside, freestanding or attached to an existing wall, and come in a great variety of sizes.