Objectives. This study aimed to compare the fracture resistance (FR) of severely damaged primary anterior teeth restored with five different post and core systems. Materials and Methods. This in vitro, experimental study evaluated 60 extracted primary maxillary central incisors. The teeth were horizontally sectioned at 1 mm above their cementoenamel junction (CEJ), underwent pulpectomy, and their root canals were filled with Metapex paste. After post space preparation and sealing of root fillings with light-cure glass ionomer (1 mm thickness), the teeth were randomly assigned to five groups (n = 12) of (1) glass fiber post and everX composite (reinforced with short fibers), (2) glass fiber post and bulk-fill composite, (3) everX composite post and core, (4) bulk-fill composite post and core, and (5) Filtek conventional composite post and core. The teeth underwent 5,000 thermal cycles between 5°C and 55°C, and their FR was measured in a universal testing machine (0.5 mm/min, 148°). The mode of failure was also determined. Data were analyzed by ANOVA and Tukey’s test at 0.05 level of significance. Results. The FR was the highest in fiber post and everX composite, and the lowest in Z250 conventional composite post and core group ( P < 0.001 ). The FR of fiber post and everX composite group was significantly higher than that of everX composite post and core ( P = 0.04 ), bulk-fill composite post and core ( P = 0.001 ), and Z250 composite post and core ( P < 0.001 ) groups. The frequency of repairable fractures was the highest in glass fiber post plus everX composite (91.66%) and the lowest in Filtek conventional post and core group (66.66%) ( P > 0.05 ). Conclusion. Within the limitations of this in vitro study, the results showed that restoration of severely damaged primary maxillary central incisors with glass fiber post and everX composite reinforced with short fibers enhanced their FR, and increased the chance of reparability in case of restoration fracture. This technique may be recommended for the restoration of primary anterior teeth since it is simple and saves time.