Abstract: The present invention comprises an insect screen and a security barrier contained within a removable frame installable to replace a conventional screen or storm window, the assembly functioning both as a barrier to insect penetration, and as a security barrier to deter an intruder from entering the building through the window or door. The main components of the window guard insert comprise a frame assembly, a security barrier, an insect screen, a spline, and a weather strip. The assembled frame includes a security barrier channel to retain the security barrier, a weather strip channel to retain the weather strip and an insect screen channel, partially formed by the security barrier to retain the insect screen. An optional clip retaining channel is used to increase the window guard insert's ability to withstand an unauthorized entry attempt.