**Self-intersecting polygons**, **crossed polygons**, or **self-crossing polygons** are polygons some of whose edges cross each other. They contrast with simple polygons, whose edges never cross. Some types of self-intersecting polygons are:

- the crossed quadrilateral, with four edges
- the antiparallelogram, a crossed quadrilateral with alternate edges of equal length
- the crossed rectangle, an antiparallelogram whose edges are two opposite sides and the two diagonals of a rectangle, hence having two edges parallel

- the antiparallelogram, a crossed quadrilateral with alternate edges of equal length
- some star polygons
- pentagram, with five edges
- heptagram, with seven edges
- octagram, with eight edges
- enneagram or nonagram, with nine edges
- decagram, with ten edges
- hendecagram, with eleven edges
- dodecagram, with twelve edges