Lipid droplets are dynamic organelles central to lipid and energy homeostasis, consisting of a hydrophobic core of neutral lipids surrounded by a phospholipid monolayer with specific proteins. They originate from the endoplasmic reticulum (ER) and interact with other organelles through membrane contact sites, playing a key role in cellular metabolism and buffering toxic lipids. Lipid droplets are essential for energy storage, signaling, and preventing lipotoxicity and oxidative stress. Their biogenesis involves neutral lipid synthesis, lens formation, and budding from the ER, with proteins like FIT and seipin playing critical roles. Lipid droplet growth and maturation occur through fusion, ER membrane bridges, and direct synthesis on the droplet surface. Proteins targeting lipid droplets include class I and II proteins, with class I proteins associated with membranes and class II proteins recruited from the cytosol. Lipid droplets interact with various organelles, including the ER, nucleus, mitochondria, peroxisomes, and lysosomes, through membrane contact sites that facilitate lipid exchange, signaling, and metabolic regulation. These interactions are crucial for lipid droplet biogenesis, maintenance, and function, highlighting their role as hubs in cellular metabolism and organelle communication.Lipid droplets are dynamic organelles central to lipid and energy homeostasis, consisting of a hydrophobic core of neutral lipids surrounded by a phospholipid monolayer with specific proteins. They originate from the endoplasmic reticulum (ER) and interact with other organelles through membrane contact sites, playing a key role in cellular metabolism and buffering toxic lipids. Lipid droplets are essential for energy storage, signaling, and preventing lipotoxicity and oxidative stress. Their biogenesis involves neutral lipid synthesis, lens formation, and budding from the ER, with proteins like FIT and seipin playing critical roles. Lipid droplet growth and maturation occur through fusion, ER membrane bridges, and direct synthesis on the droplet surface. Proteins targeting lipid droplets include class I and II proteins, with class I proteins associated with membranes and class II proteins recruited from the cytosol. Lipid droplets interact with various organelles, including the ER, nucleus, mitochondria, peroxisomes, and lysosomes, through membrane contact sites that facilitate lipid exchange, signaling, and metabolic regulation. These interactions are crucial for lipid droplet biogenesis, maintenance, and function, highlighting their role as hubs in cellular metabolism and organelle communication.