Maternal obesity impairs placental function, affecting fetal growth and long-term health. Although fermented wheat germ (FWG) provides health benefits, its impact on maternal obesity-related metabolic disorders and placental function remains unclear. This study investigated FWG's effects on placental morphology, metabolism, and nutrient transport in high-fat diet (HFD)-induced obese maternal rats. Wheat germ (WG) and FWG were administered from model induction, with a 45% HFD-fed for 10 weeks before conception and continued until gestational day 19.5. Results revealed that WG and FWG supplementation alleviated maternal metabolic abnormalities and mitigated placental structural damage. Additionally, this supplementation reduced placental lipid accumulation, oxidative stress, and inflammation while regulating nutrient transporter mRNA expression and inhibiting mTOR signaling activation. Compared with WG, FWG more effectively reduced maternal obesity and optimized placental nutrient transport. These findings suggest that FWG is a promising dietary intervention for disrupting the maternal obesity cycle and enhancing maternal-fetal health by alleviating obesity, mitigating metabolic dysfunction, and modulating placental morphology and function.