Background: Glucocorticoid (GC) is the first?line therapy for asthma, but some asthmatics are insensitive to it. Glucocorticoid?induced transcript 1 gene (GLCCI1) is reported to be associated with GCs efficiency in asthmatics, while its exact mechanism remains unknown. Methods: A total of 30 asthmatic patients received fluticasone propionate for 12 weeks. Forced expiratory volume in 1 s (FEV1) and GLCCI1 expression were detected. Asthma model was constructed in wild?type and GLCCI1 knockout (GLCCI1?/?) mice. Glucocorticoid receptor (GR) and mitogen?activated protein kinase phosphatase 1 (MKP?1) expression were detected by polymerase chain reaction and West blotting (WB). The phosphorylation of p38 mitogen?activated protein kinase (MAPK) was also detected by WB. Results: In asthmatic patients, the change of FEV1 was well positively correlated with change of GLCCI1 expression (r = 0.430, P = 0.022). In animal experiment, GR and MKP?1 mRNA levels were significantly decreased in asthmatic mice than in control mice (wild?type: GR: 0.769 vs. 1.000, P = 0.022; MKP?1: 0.493 vs. 1.000, P < 0.001. GLCCI1?/?: GR: 0.629 vs. 1.645, P < 0.001; MKP?1: 0.377 vs. 2.146, P < 0.001). Hydroprednisone treatment significantly increased GR and MKP?1 mRNA expression levels than in asthmatic groups; however, GLCCI1?/?.asthmatic mice had less improvement (wild?type: GR: 1.517 vs. 0.769, P = 0.023; MKP?1: 1.036 vs. 0.493, P = 0.003. GLCCI1?/?: GR: 0.846 vs. 0.629, P = 0.116; MKP?1: 0.475 vs. 0.377, P = 0.388). GLCCI1?/? asthmatic mice had more obvious phosphorylation of p38 MAPK than wild?type asthmatic mice (9.060 vs. 3.484, P < 0.001). It was still higher even though after hydroprednisone treatment (6.440 vs. 2.630, P < 0.001). Conclusions: GLCCI1 deficiency in asthmatic mice inhibits the activation of GR and MKP?1 and leads to more obvious phosphorylation of p38 MAPK, leading to a decremental sensitivity to GCs.