Abstract: A security window assembly includes a frame coupled to an opening in a structure, a first window section coupled to the frame, and a second window section slidable within the frame relative to the first window section, where the second window section has a closed position where the first window section and the second window section substantially fill different portions of the opening and an open position where the first window section and the second window section substantially fully overlap each other. A security panel is coupled to the second window section so that the security panel is stowed within the structure when the second window section is in the closed position and at least partially fills the opening when the second window section is in the open position.