Phospholipase D (PLD) is a key enzyme in biotic and abiotic stress responses and is involved in a variety of biological signal transduction mechanisms with possible biotechnological uses. Studies in several plant species have proven PLD participation in signal transduction and demonstrated the biotechnological implications of a clearer understanding of intracellular communication. The molecular structure and biochemical characteristics of different PLD in plants have been documented, helping to better describe its genetics. Description of this enzyme’s molecular sequence has allowed biochemical analyses aimed at evaluating plant responses to environmental conditions and their effect on PLD expression. Determining the signal transduction mechanism and PLD’s functions will facilitate understanding of the molecular process behind stress perception, consequent intercellular actions and PLD’s physiological effects. A deeper knowledge of PLD will suggest biotechnological applications and could lead to use of novel enzymes with attractive properties in different lipid transformation processes and future transformations mediated by plant-source enzymes. This review covers current research on plant PLD and its possible biotechnological uses.