Immunoglobulin G (IgG) is recognized as a key regulator of metabolic dysfunction and fibrosis in adipose tissue, and its functional properties are tightly regulated by its glycosylation profile. However, the role of IgG glycosylation in adipose aging remains unclear. Here, we performed transcriptomic and glycoproteomic analyses of epididymal white adipose tissue (eWAT) from young and aged mice. RNA sequencing (RNA-seq) analysis revealed a significant downregulation of adipogenic genes in aged eWAT, accompanied by elevated expression levels of inflammatory and fibrotic markers, which were further validated by quantitative polymerase chain reaction (qPCR). N- and O-glycoproteomic analyses revealed widespread changes in glycosylation. Differentially glycosylated proteins are primarily localized to the extracellular space and participate in innate immune responses, transport and signal transduction, extracellular matrix (ECM)-receptor interaction pathways, and so on. Notably, IgG glycosylation levels were significantly increased in aged mice. Specifically, the N-fucosylation of IgG1, IgG2a, and IgG3 was elevated by 3.1-, 10.4-, and 3.2-fold, respectively, while only IgG2a showed increased O-fucosylation. These findings suggest that N-fucosylation is a common age-related modification across IgG subtypes. Using in vivo models, we further demonstrated that B-cell depletion-induced IgG reduction increased adipogenic and inflammatory gene expression, while the expression of fibrotic markers was suppressed. These effects were reversed upon repletion with either fucosylated or nonfucosylated IgG. Importantly, compared with nonfucosylated IgG, fucosylated IgG exacerbated inflammation and fibrosis but inhibited adipogenesis more strongly. Taken together, our results identify fucosylated IgG as a key mediator of adipose dysfunction during aging and suggest that modulating IgG fucosylation may offer therapeutic potential for age-related metabolic disorders.