Turmeric, derived from , and , a lactic acid bacteria, have been studied for their potential antiobesity effects. To date, the antiobesity effects of turmeric fermented with have not been sufficiently investigated. This study was conducted oral administration of 5% fermented (FT) and unfermented turmeric (UT) in diet over 16 weeks using high-fat diet (HFD)-induced obese C57BL/6J mice. Results showed that the curcuminoid content of turmeric decreased following fermentation. Furthermore, FT significantly suppressed weight gain and liver and visceral adipose tissue weight and reduced plasma metabolic parameters in both the UT and FT experimental groups. The effects of FT were more noticeable than those of the unfermented form. Moreover, FT downregulated the expression of adipogenesis, lipogenesis, and inflammatory-related protein, but upregulated liver β-oxidation protein SIRT 1, PPARα, and PGC-1α in perigonadal adipose tissue. Additionally, FT ameliorated insulin resistance by activating insulin receptor pathway protein expressions in visceral adipose tissues. FT also modulated gut microbiota composition, particularly in two beneficial bacteria, and as well as two short-chain fatty acid-producing bacteria: and . Our findings indicate that the modulation effect of FT may be an important pathway for its antiobesity mechanisms.