A space truss or space frame structure utilizes a three-dimensional truss to resist lateral forces. Unlike a normal truss, in which horizontal, vertical, and diagonal members work together on a single plane, a space truss uses diagonal connections which branch outside of the plane. A space truss usually looks like several interlocking pyramidal outlines.

The connections extend through space rather than remaining in one flat truss plane. Several planar-looking outlines can therefore belong to a single connected three-dimensional arrangement.

Interlocking pyramidal outlines are a usual appearance rather than a required decorative pattern. The out-of-plane structural connections distinguish the space truss from a flat braced frame.