Objective: Antiganglioside antibodies (AGAs) play a crucial role in the pathogenesis of Guillain–Barré syndrome (GBS). We aim to explore the relationship between thyroid autoantibodies and AGAs in GBS patients. Methods: We selected 60 GBS patients who were admitted to Nanjing Drum Tower Hospital from July 2018 to February 2023 and tested for both anti-thyroid antibodies and AGAs levels. According to anti-thyroid antibodies, the patients were divided into normal group and abnormal group. The clinical characteristics, thyroid function and the proportion of AGAs in the two groups were compared. Results: Compared with the normal group, GBS patients in the abnormal group had significantly increased anti-GM1 antibodies (p<0.05) and anti-GM2 antibodies (p<0.05), and were accompanied by more severe clinical symptoms (p<0.05). Multivariate logistic regression analysis showed that the presence of abnormal anti-thyroid antibodies (OR=5.184, 95%CI [1.377, 19.518], p=0.015) and increased free thyroxine (FT4) levels (OR=1.266, 95%CI [1.009, 1.588], p=0.030) were independent risk factors for increased anti-GM1 antibody positive rate in GBS patients. ROC curve analysis found that the optimal threshold for TPO-Ab to predict anti-GM1 Ab positive was 47.9 IU/mL, with a sensitivity of 66.7% and a specificity of 77.8%. The optimal threshold for Tg-Ab to predict anti-GM1 Ab positive was 20.0 IU/mL, with a sensitivity of 73.3% and a specificity of 73.3%. Conclusion: Our results suggest an association between thyroid autoantibodies and anti-GM1 antibody in GBS patients, potentially explaining the poorer prognosis of GBS patients with thyroid dysfunction.