Emerging evidence indicates that hypnotic anesthetics affect immune function. Many anesthetics potentiate -aminobutyric acid A receptor (GABA_AR) activation, and these receptors are expressed on multiple subtypes of immune cells, providing a potential mechanistic link. Like immune cells, airway smooth muscle (ASM) cells also express GABA_ARs, particularly isoforms containing α4 subunits, and activation of these receptors leads to ASM relaxation. We sought to determine if GABA_AR signaling modulates the ASM contractile and inflammatory phenotype of a murine allergic asthma model utilizing GABA_AR α4 subunit global knockout (KO; Gabra4^0/0) mice. Wild type (WT) and Gabra4 KO mice were sensitized with house dust mite (HDM) antigen or exposed to phosphate buffered saline (PBS) intranasally 5 days/week for 3 weeks. Ex vivo tracheal rings from HDM-sensitized WT and Gabra4 KO mice exhibited similar magnitudes of acetylcholine-induced contractile force and isoproterenol-induced relaxation (p=n.s.; n=4). In contrast, in vivo airway resistance (flexiVent) was significantly increased in Gabra4 KO mice (p<0.05, n=8). Moreover, the Gabra4 KO mice demonstrated increased eosinophilic lung infiltration (p<0.05; n=4), and increased markers of lung T cell activation/memory (CD62L low, CD44 high; p<0.01, n=4). In vitro, Gabra4 KO CD4⁺ cells produced increased cytokines and exhibited increased proliferation after stimulation of the T cell receptor as compared to WT CD4⁺ cells. These data suggest that the GABA_AR α4 subunit plays a role in immune cell function during allergic lung sensitization. Thus, GABA_AR α4 subunit-specific agonists have the therapeutic potential to treat asthma via two mechanisms: direct ASM relaxation and inhibition of airway inflammation.