AbstractLight steel frame (LSF) building systems are a fast, reliable and economical construction system for residential and non‐residential buildings. Since the thermal conductivity of steel significantly limits the effectiveness of such wall systems for use in modern energy‐efficient buildings, adequate thermal insulation is essential. For this reason, numerous research studies have been conducted on LSF structures with different types and positions of thermal insulation. Due to the combustible nature of polymer foam, LSF systems insulated with this type of insulation have not been the focus of this research. On the other hand, polymer foam is ideal for automated industrial production of prefabricated load‐bearing LSF walls, and research on such walls is mandatory. In this paper, the fire test results of two innovative LSF walls with polymer foam insulation and different gypsum fibreboards are presented. In the proposed configuration, spacers are also used to prevent direct contact between the wall panels and the steel studs. The study conducted shows that a suitable configuration of gypsum fibreboards can lead to satisfactory fire resistance of energy‐efficient LSF wall systems with polymer foam.