High fat diet (HFD) induces hyperlipidemia and causes non-alcoholic fatty liver disease. Cinnamon (Cinnamomum zeylanicum) has many curative effects as anti-inflammatory and antioxidant. This study aimed to investigate the potential protective effect of cinnamon against HFD-induced dyslipidemia and liver steatosis. Forty adult male Wistar albino rats were used in the current study; these were allotted randomly to 4 equal groups. The animals were fed on standard diet (group 1), standard diet containing cinnamon powder “15% weight by weight, w/w" (group 2), HFD (group 3), or HFD containing cinnamon powder “15% w/w" (group 4) daily for 4 or 8 weeks. The results showed that HFD increased significantly (P≤0.05) the body weight and the activities of serum aminotransferases, and induced dyslipidemia. Examination of the liver of the HFD-fed rats showed many pathological changes, especially intracytoplasmic fat accumulation either as small lipid droplets with variable sizes (microsteatosis) or large lipid droplets (macrostatosis) that may displace the nucleus laterally. Ultrastructural examination of the same group showed various degenerative alterations in the nucleus, mitochondria, endoplasmic reticulum, and Kupffer cells, as well as lipid accumulation. However, examination of liver of animals fed on HFD+cinnamon showed a remarkable improvement especially after 8 weeks; the histological and ultrastructure pictures were mostly similar to the control group. In addition, the animals fed on HFD+cinnamon recorded a decrease in the body weight and improvement in readings of the biochemical parameters compared with the HFD-treated group. In conclusion, cinnamon alleviated the occurrence of non-alcoholic fatty liver disease in the HFD-fed rats.