The present study was conducted to determine the effects of dietary heat killed Lactobacillus plantarum (HK L- 137) on growth, survival, and immune response of juvenile striped catfish (Pangasianodon hypophthalmus). Feeding trial was carried out and four replicates groups of experimental fish (initial wt. 0.06 g) were fed with respective test diets containing four different concentrations of HK L-137 (0 ppm-control diet), 10 ppm, 20 ppm and 50 ppm, respectively. At the end of the feeding trial, results showed that the dietary supplementation of HK L-137 significantly enhanced the final weight (Wf), weight gain (WG) and specific growth rate (SGR) of juvenile striped catfish fed the diets containing 20 ppm and 50 ppm HK L-137 (pfed the diet contains 50 ppm HK L-137 was significantly higher than the HK L-137 free group of fish fed with control diet (precorded in HK L-137 supplemented groups. Moreover, feed conversion ratio (FCR) of HK L-137 supplemented groups were also significantly lower than the control group. Furthermore, the dietary supplementation of HK L-137 improved and augmented the immune parameters including lysozyme activity, the number of RBC and WBC of juvenile striped catfish. Thereafter, a 14- day bacterial challenge experiment was also carried out and the highest mortality rate (100%) was recorded in positive-control group of fish fed with control diet. Consequently, post challenge survival rates (PCSR) of HK L-137 supplemented groups were higher than the control group. Present study demonstrated that the dietary supplementation of HK L-137 has the tremendous positive-effects on SR, FCR, WG, SGR, FI, PER, immune response and disease resistance of juvenile striped catfish.