Background & Aims: Missense mutations in human Kr�ppel-like factor 11 (KLF11) lead to the development of diabetes as a result of impaired insulin synthesis in the pancreas. However, the role of KLF11 in peripheral tissues is largely unknown. The objective of this study is to evaluate the role of KLF11 in the regulation of hepatic lipid homeostasis using different mouse models. Methods: Adenoviruses expressing KLF11 (Ad-KLF11) or KLF11-specific shRNA (Ad-shKLF11) were injected into db/db diabetic, high-fat diet-induced obese (DIO), or normal C57BL/6J mice. Histological analysis of fatty liver phenotype and biochemical analysis of hepatic and serum TG levels in these mice were performed. The molecular mechanism by which KLF11 regulates lipid metabolism in primary hepatocytes and mice livers was explored. Results: The expression of the transcription factor KLF11 gene is dysregulated in the livers of db/db and DIO mice. Adenovirus-mediated overexpression of KLF11 in the livers of db/db and DIO mice activates the PPAR? signaling pathway, subsequently markedly improving the fatty liver phenotype. Conversely, knockdown of KLF11 by adenovirus (Ad-shKLF11) in livers of wild-type C57BL/6J and db/m mice increases hepatic triglyceride (TG) levels, owing to decreased fatty acid oxidation. Finally, the treatment of diabetic mice with Ad-shPPAR? abolishes the KLF11 stimulatory effects on expression of genes involved in fatty acid oxidation and inhibitory effects on hepatic TG content. In contrast, PPAR? rescue restores the increased hepatic TG levels in Ad-shKLF11-infected db/m mice to normal levels. Conclusions: KLF11 is an important regulator of hepatic lipid metabolism.