Phospholipids, including phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylserine (PS) and phosphoinositides, have emerged as an important class of cellular messenger molecules in various cellular and physiological processes, of which PA attracts much attention of researchers. In addition to its effect on stimulating vesicle trafficking, many studies have demonstrated that PA plays a crucial role in various signaling pathways by binding target proteins and regulating their activity and subcellular localization. Here, we summarize the functional mechanisms and target proteins underlying PA‐mediated regulation of cellular signaling, development, hormonal responses, and stress responses in plants. Phosphatidic acid has emerged as an important cellular messenger in various cellular and physiological processes, which functions by binding target proteins and regulating their activities and subcellular localizations. In this review, we summarize the functional mechanisms underlying PA‐mediated regulation of cellular signaling, development, hormonal responses, and stress responses in plants.