A systematic review and meta-analysis of prospective randomized studies were performed to evaluate the diagnostic value of measuring global longitudinal strain (GLS) using speckle tracking echocardiography (STE) in determining myocardial infarction (MI) size, which is usually measured based on late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR). Eleven trials with a total of 765 patients were included. The pooled correlation was 0.70 (95% CI: 0.64, 0.74) between two-dimensional (2D) GLS and the LGE percentage, and it was 0.55 (95% CI: 0.19, 0.78) for three-dimensional (3D) GLS. Pooled diagnostic estimates for 2D GLS to differentiate an MI size >12% were as follows: sensitivity, 0.77 (95% CI: 0.61, 0.90); specificity, 0.86 (95% CI: 0.68, 0.96); positive likelihood ratio (PLR), 8.13 (95% CI: 1.90, 26.61); negative likelihood ratio (NLR), 0.28 (95% CI: 0.10, 0.54); and diagnostic odds ratio (DOR), 39.87 (95% CI: 4.12, 172.83). The estimated area under the curve (AUC) of the summary receiver operating characteristic (SROC) curve was 0.702. The 2D STE results positively correlated with the infarction size quantified by CMR for patients who had experienced their first MI. This approach can serve as a good diagnostic index for assessing infarction area. However, more consolidated STE studies are still needed to determine the value of 3D STE.