Background: Heart failure with preserved ejection fraction (HFpEF), an increasing public health concern, is increasing in prevalence and is associated with an elevated risk of hospitalization and mortality. Currently, data on the clinical application value of left ventricular global longitudinal strain (LV GLS) in HFpEF are contradictory. Therefore, we performed the following meta-analysis to appraise the diagnostic and prognostic value of LV GLS in HFpEF. Methods: PubMed, Medline, Scopus, and Web of Science were retrieved exhaustively from their inception until December 20, 2022, to obtain literature assessing the diagnostic and prognostic value of LV GLS in HFpEF. Results: Forty-one studies (including 14,543 patients) published from 2008 to 2022 were included. The results of the meta-analysis were as follows: First, the LV GLS values in HFpEF patients were significantly lower than in healthy individuals (SMD:1.21; 95% CI (0.94, 1.47), p<0.00001, I²=85%; P<0.00001), but substantially higher than in HErEF patients (SMD: -2.03; 95% CI (-2.23, -1.72), p<0.00001, I²=92%; P<0.00001). Second, the pooled diagnostic parameters of LV GLS for HFpEF were as follows: sensitivity, 0.77 (95% CI: 0.71–0.82); specificity, 0.66 (95% CI: 0.58–0.74); DOR, 7.53 (95% CI: 3.19–17.74); AUC for the SROC, 0.81 (95% CI: 0.79–0.87). Finally, the low LV GLS values in HFpEF patients were correlated with a higher risk of all-cause death (HR: 1.12; 95% CI: 1.01-1.25; p=0.000, I2=84%; P=0.031). Conclusions: LV GLS is impaired in HFpEF patients despite a normal left ventricular ejection fraction, indicating the existence of mild LV contractile dysfunction. Moreover, LV GLS might be an auxiliary indicator for diagnosing HFpEF and predicting all-cause death in HFpEF patients.