<p><strong>Objective: </strong>The present study aims to evaluate the antidiabetic effect of ethanolic extract of <em>Haematococcus pluvialis (H. pluvialis) </em>in streptozotocin (STZ)-induced diabetic rats.</p><p><strong>Methods: </strong>The antidiabetic activity of <em>H. pluvialis </em>was investigated by the determination of glucose and insulin levels, aspartate (AST), alanine transaminases (ALT), lipid profile including total cholesterol (TC), triglycerides (TG), low-density lipoprotein-cholesterol (LDL-C) and high-density-lipoprotein-cholesterol (HDL-C). Histopathological examination of pancreas and liver were also carried out.</p><p><strong>Results: </strong>The results revealed that the levels of glucose, TC, TG, LDL-C as well as AST and ALT enzyme activities were increased significantly in diabetic rats. While, insulin and HDL-C levels decreased significantly in STZ-induced diabetic rats. The remediation of diabetic rats with <em>H. pluvialis</em> attenuated the elevated levels of glucose, TC, TG, LDL-C as well as AST and ALT activities in diabetic rats. Besides, it improved insulin, HDL-C levels, pancreas and hepatic architectures.<strong></strong></p><p><strong>Conclusion: </strong><em>H. pluvialis</em> extract has a promising antidiabetic potency through attenuation of several metabolic disorders associated diabetes.<strong></strong></p>