This research aims to investigate the effects of employing steel fibers in exterior reinforced concrete (RC) beam-column joints (BCJs) and evaluate the variations of seismic ductility behavior at ambient temperature and after fire exposure. For this purpose, six scaled RC BCJs were fabricated with the same dimensional properties and with three different values of stirrup ratio () at the joint core. For each value of stirrup ratio, two similar BCJs were considered for the lateral cyclic loading at ambient temperature and after exposure to a 600℃ heating regime. The evaluation of variations was conducted relative to two control BCJs by employing steel fibers (SFs) by 1% volume fraction (VF)in consumed concrete, as well as by applying two different reduction rates to the initial value of =0.0063 (for two control BCJs without fibers). Such changes improved ductility and energy dissipation significantly at ambient temperature, but resulted in a relatively different trend of variations for the post-fire performance. In this regard, the employment of SFs along with the reduction in the initial stirrup ratio by 42.9% and 60% was accompanied by remarkable enhancements in ductility ratio (DR) by 57.39% and 26.32%, as well as by smaller increments of 14.16% and 10.73% after fire exposure, respectively. The cumulative energy dissipation (CED) variations also indicated that employing SFs simultaneously with the mentioned changes in the stirrup ratio was accompanied by increments of 28.94% and 3.75%, respectively, at ambient temperature, while the variations were found as a 2.50% increase in DR and a 10.86% decrease in the CED after fire exposure.