Increased anthropogenic activities in the last century have aggravated diverse chemical pollutants in the environment. Among these pollutants, xenobiotics are chemicals or other substances that plants cannot utilize, leading to toxic effects or altering the normal function of metabolic processes. Xenobiotics originate from various sources, such as environmental pollutants, pesticides, herbicides, household cleaning products, and many more. Different xenobiotics affect plants in other ways, and it is now an important area of research to understand coordinated signaling pathways that alter the gene expression and regulation of higher plants. In this respect, gene expressions and the roles of different enzymes for the mobilization and detoxification of xenobiotics must be explored further. Therefore, in this chapter, the various roles of genes and enzymes in the signaling and detoxification processes of xenobiotics in plant systems are discussed in detail.