Using the first-principles full-potential linear muffin-tin orbital (FP-LMTO) method based on density functional theory, we have investigated the electronic structure and magnetism of order dilute ferromagnetic semiconductor Al1−xCrxP (x = 0.125, 0.25 and 0.50) and the superlattices (AlP)1/(CrP)1 and (AlP)3/(CrP)1. For the exchange-correlation functional, the generalized gradient approximation (GGA) has been used. It is shown that these compounds are half-metallic ferromagnets. Calculations of the s-d exchange constant N0α and p-d exchange constant N0β clearly indicate the magnetic nature of these compounds. We observe that p-d hybridization reduces the local magnetic moment of Cr from its free space charge value and produces small local magnetic moments on the non-magnetic Al and P sites.