  We present several Orientifolds of M-Theory on $K_3\times S^1$ by additional
projections with respect to the finite abelian automorphism groups of $K_3$.
The resulting models correspond to anomaly free theories in six dimensions. We
construct explicit examples which can be interpreted as models with eight,
four, two and one vector multiplets and $N=1$ supersymmetry in six dimensions.

High Energy Physics - Theory