A self-disinfecting medication vial cap assembly for a medication vial includes a needle-penetrable assembly base configured for attachment to the medication vial; an assembly cap carried by the assembly base, the assembly base and the assembly cap having a cap interior and the assembly cap positional between closed and open positions; a rupturable antiseptic pouch attached to the assembly base and the assembly cap in the cap interior; and an antiseptic contained in the antiseptic pouch. The antiseptic pouch remains intact in the closed position of the assembly cap. The antiseptic pouch ruptures and the antiseptic is discharged onto the assembly base upon movement of the assembly cap from the closed position to the open position.