Sirtuins are energy sensors which mediate effects of calorie restriction-induced lifespan extension. The mammalian sirtuin homolog SIRT1 is a protein deacetylase playing a central role in metabolic homeostasis. SIRT1 is one of the targets of resveratrol, a polyphenol that has been shown to increase lifespan and to protect animal models against high-calorie diet induced obesity and insulin resistance. The beneficial effects of resveratrol mediated by SIRT1 activation can be contributed by different organs. Among them, the liver and pancreatic β-cells have been shown to be responsive to resveratrol in a SIRT1-dependent manner. Downstream of SIRT1, transcription factors being activated are tissue-specific, in turn inducing expression of metabolic genes in an apparent paradoxical way. In this review, we discuss specificities of SIRT1 effects in the liver versus pancreatic β-cells, ultimately converging towards metabolic homeostasis at the organism level.