Introduction: The triglyceride-glucose (TyG) index is reported to be related to poor functional outcomes and all-cause mortality post-stroke. However, the association between TyG index and recurrent stroke after acute ischemic stroke (AIS) has not been well described. We aimed to identify whether the TyG index was associated with 1-year recurrent stroke after AIS. Methods: Baseline patient information was collected at admission, and the TyG index was calculated. Recurrent stroke events were followed up at 1, 3, 6, and 12 months after diagnosis. We then examined the association between the TyG index and risk of 1-year recurrent stroke using multivariable Cox regression models and restricted cubic spline analyses. Results: Among 2,288 participants, the mean TyG index was 8.8 ± 0.7. Those in the fourth quartile (Q4) demonstrated higher recurrent stroke risk than those in Q1 (adjusted hazard ratio [HR] = 1.63; 95% confidence interval [CI], 0.98–2.72; p = 0.059). Subgroup analysis revealed a sex-specific association between TyG index and recurrent stroke (p for interaction = 0.022). Additionally, restricted cubic splines analyses showed a nonlinear association between the TyG index and 1-year recurrent stroke. In females, patients in the Q4 had a 2.95-fold increased recurrent stroke risk than did patients in the Q1 (adjusted HR = 2.95; 95% CI: 1.09–7.94; p = 0.032); the risk increased when the TyG index was >8.73. However, no significant correlation was observed in males. Conclusion: A nonlinear association was found between the TyG index and 1-year recurrent stroke risk. Subsequently, a high TyG index could predict an increased 1-year recurrent stroke risk in female AIS patients.