A tautliner is a special form of a truck trailer with a side sliding tarpaulin installed.

This means that goods can be loaded and unloaded more quickly and easily or repositioned on the loading area. This also increases the lateral loading length. The term comes from the English "taut" (for taut or stretched) and "liner" (for means of transport). In Germany, the tautliner is often referred to as a curtain-sided semi-trailer. There are no side walls and instead only one tarpaulin is lashed down. The load must therefore be secured separately. Often both side tarpaulins can also be opened, which makes loading more flexible.