Myocardial infarction with non-obstructive coronary arteries (MINOCA) represents a heterogeneous clinical entity encompassing multiple ischemic mechanisms, including atherosclerotic plaque disruption, coronary artery spasm, coronary microvascular dysfunction, coronary embolism, and spontaneous coronary artery dissection. Despite the absence of obstructive coronary disease, patients with MINOCA remain at substantial risk of adverse cardiovascular outcomes, underscoring the need for accurate early diagnosis and effective risk stratification. In this context, accumulating evidence indicates that circulating serum biomarkers may provide additional pathophysiological and prognostic insights in patients with a working diagnosis of MINOCA. Moreover, distinct biomarker profiles may help support the differential diagnostic evaluation between MINOCA and other causes of acute myocardial injury, such as myocardial infarction with obstructive coronary arteries, myocarditis, and Takotsubo syndrome. This narrative review summarizes current evidence on serum biomarkers in MINOCA, highlights their potential role in guiding tailored diagnostic strategies, and discusses future perspectives toward biomarker-driven precision medicine in patients presenting with acute myocardial injury.