Dietary manipulations play an important role in mitigating the negative impacts of heat stress (HS) on farm animals. Thus, this study was conducted to examine the modulatory role of spirulina platensis (SP) in improving the growth performance, biochemical parameters, antioxidant status, and immunological response of suckling Egyptian buffalo calves during summer season. A total of 24 newly born calves were randomly allotted to groups of six calves in each group. Group (1) served as the control. The other three groups were received suckling milk supplemented with SP powder at levels; 5 g/head/day (SP5), 10 g/head/day (SP10) and 15 g/head/day (SP15) for three months suckling period. Results showed that the values of average daily gain in the SP10 or SP15 groups were greater significantly (P<0.05) than those in the control group. The values of total protein, albumin, globulin, high density lipoproteins, red blood cells, hemoglobin, white blood cells, lymphocytes, and platelet count were significantly higher in SP- treated groups than those in the control group. Liver enzymes activities, urea, creatinine, low density lipoproteins, glucose and bilirubin did not affect significantly by the SP supplement. The concentrations of total cholesterol and triglycerides as well as lipid peroxidation were significantly lower (p<0.05) in the SP15 group than the control. Redox status and immunity parameters were improved in the SP10 and SP15 groups compared to the control. In conclusion, dietary SP 10 or 15 g SP/ Head /day can mitigate the harmful influences of heat stressed on suckling buffalo calves, via boosting the immunological parameters and antioxidant capacity.