The abundance of silicon (Si) in the earth's crust is found as silicon dioxide (SiO2). But this abundance of Si is not a sign that the plants take up an adequate amount of Si. This review article incorporates research based on Si to understand the importance of Si in plants under various stress conditions and its role in sustainable agricultural production. Si's application is considered a better approach to providing stress tolerance to plants under stress conditions. The review describes the different phases of Si, its absorption, transport in plants, and its various mechanisms of action to tolerate specific stresses. The uptake and transport of Si through various Si transporters have also been reported. This review also discusses the various mechanisms of Si under biotic or abiotic stress in different plants. The application of Si improves soil quality and soil health and enhances the soil microbial population. In addition, the role of Si in the upregulation and down-regulation of proteins under stressful conditions has also been reported. The information can help to better understand the importance and mechanism of Si in plants and its application in agriculture.