Background: The impact of maternal obesity on offspring health remains a major and pressing issue. We investigated its impact on the development of the infant gut microbiome during the first six months of life, examining the taxonomic composition, metabolic pathways, and antibiotic resistance genes. Methods: Twenty-four mother–infant pairs were divided into maternally obese (OB, BMI > 36) and normal weight (BM) groups. Shotgun metagenomic sequencing was performed on stool samples collected at birth and at 1, 3, and 6 months. A total of 12 maternal samples and 23 infant samples (n = 35) in the obese group and 12 maternal samples and 30 infant samples (n = 42) in the control group were sequenced. The analysis included taxonomic profiling (MetaPhlAn 4), metabolic pathway analysis (HUMAnN 3), and antibiotic resistance gene screening (CARD/ABRicate). Results: The OB group showed reduced alpha diversity in the first month (p ≤ 0.01) and an increased Firmicutes/Bacteroidetes ratio, peaking at 3 months (p ≤ 0.001). The metabolic profiling revealed enhanced carbohydrate breakdown (p ≤ 0.001) in the BM group and lipid biosynthesis (p ≤ 0.0001) in the OB group pathways. Strong correlations emerged between Lactobacillales and fatty acid biosynthesis (r = 0.7, p ≤ 0.0001) and between Firmicutes and lincosamide (r = 0.8, p ≤ 0.0001). Conclusions: The infants of obese mothers had significantly altered development of the infant gut microbiome, affecting both composition and metabolic potential. These changes may have long-term health consequences and suggest potential therapeutic targets for intervention.