The role of inflammation in psychiatric disorders, such as anxiety, has gained increasing attention, with the hippocampus being identified as a key region involved in emotional regulation. Argon has been reported to alleviate the symptoms of psychiatric disorders; however, its underlying mechanism remains unclear. In this study, we found that argon significantly suppressed lipopolysaccharide-induced anxiety-like behaviors and attenuated hippocampal neuronal hyperexcitability in mice. By analyzing neuronal excitability following microglial depletion and subsequent repopulation, as well as assessing microglial morphology, we confirmed that microglia are key targets of inflammation and validated the inhibitory effects of argon. Electrophysiological studies and transcriptome sequencing revealed that argon inhibited the microglia-released inflammatory cytokines via the Toll-like receptor 4/nuclear factor-κB signaling pathway, thereby improving the excitability of hippocampal neurons. Collectively, this study provides evidence that the regulation of microglia may be the underlying mechanism by which argon ameliorates neuroinflammation-induced anxiety-like behaviors.