Previous studies have demonstrated that the underlying mechanisms of myocardial ischemia/reperfusion injury (MIRI) are complex and involve multiple types of regulatory cell death, including ferroptosis, apoptosis, and autophagy. Thus, we aimed to identify the mechanisms underlying MIRI and validate the protective role of epigallocatechin-3-gallate (EGCG) and its related mechanisms in MIRI. An in vivo and in vitro models of MIRI were constructed. The results showed that pretreatment with EGCG could attenuate MIRI, as indicated by increased cell viability, reduced lactate dehydrogenase (LDH) activity and apoptosis, inhibited iron overload, abnormal lipid metabolism, preserved mitochondrial function, decreased infarct size, maintained cardiac function, decreased reactive oxygen species (ROS) level, and reduced TUNEL-positive cells. Additionally, EGCG pretreatment could attenuate ferroptosis, apoptosis, and autophagy induced by MIRI via upregulating 14–3–3η protein levels. Furthermore, the protective effects of EGCG could be abolished with pAd/14–3–3η-shRNA or Compound C11 (a 14–3–3η inhibitor) but not pAd/NC-shRNA. In conclusion, EGCG pretreatment attenuated ferroptosis, apoptosis, and autophagy by mediating 14–3–3η and protected cardiomyocytes against MIRI.