Abstract: A window storm shield and guard assembly installable to fit within the jamb of a building window, or to fit onto the face of the building surrounding the jamb, the assembly, functioning both as a storm barrier to protect the window from strong winds and wind-borne debris, and as a security barrier to deter an intruder from entering the building through the window. The main components of the assembly are a main frame defining a rectangular socket, and a barrier frame which is normally nested in the socket and supports a perforated metal barrier panel that reduces but does not block the passage of light and the flow of air through the panel. The barrier frame is hinged at its upper end to the corresponding end of the main frame, and at its lower end, the barrier frame is latched internally to the corresponding end of the main frame. In the closed mode of the assembly in which the barrier frame is nested in the main frame and is latched thereto, the window is then fully protected.