In this paper we discuss the concepts of “measure of chirality” and “degree of chirality” as functions of the shape of a molecular model M. The measure of chirality χ( M) is defined as a continuous, real-valued, and similarity-invariant function of M such that χ( M) = 0 when M is achiral, and χ( M')= −χ( M), where M' is the enantiomorph of M. The degree of chirality is defined as ¦χ( M) ¦. We discuss the application of one such function, based on the idea of maximal overlap (superimposition) of M and M' to tetrahedra, simplexes in E 3. An analysis of the properties of this function leads to the conclusion that, although a least chiral tetrahedron exists, the most chiral one might only be approachable as a limit. A rigorous analytical study of the corresponding function for triangles, simplexes in E 2, serves to illustrate this conclusion.