Abstract: Disclosed is a skylight structure capable of meeting the ASTM E-108 Class A fire rating requirements. In the illustrated embodiment, the structure comprises upper and lower thermoplastic panels maintained in parallel spaced relation by a gridwork of transversely extending metal beams, which maintain a metal screen taut adjacent the lower polymeric panel, and a layer of light transmitting insulating material disposed immediately above the screen. The metal gridwork and metal screen assure that no burning particles pass through the skylight structure and into the building, so that the upper and lower panels may be formed of very efficient light transmitting thermoplastics and do not need to be formed of thermoset plastics, which are less efficient at light transmission, but previously employed for its retardation characteristics. Hence, the disclosed skylight structure provides improved light transmission and improved fire resistance over currently manufacture skylights.