Sheet piles are sections of sheet materials with interlocking edges that are driven into the ground to provide earth retention and excavation support. Sheet piles are most commonly made of steel, but can also be formed of timber or reinforced concrete. They are installed in sequence to design depth along the planned excavation perimeter or seawall alignment. The interlocked sheet piles form a wall for permanent or temporary lateral earth support with reduced groundwater inflow. Anchors can be included to provide additional lateral support if required.

Sheet piles are commonly used for retaining walls, land reclamation, underground structures such as car parks and basements, in marine locations for riverbank protection, seawalls, cofferdams, and so on. Permanent steel sheet piles are designed to provide a long service life. Vibratory hammers are typically used to install sheet piles. If soils are too hard or dense, an impact hammer can be used to complete the installation. For the development of sheet piles, there are two main techniques: hot-rolled and cold-formed. At high temperatures, hot rolled piles are produced and the interlocks appear to be stronger and more resilient.