Among the various biological approaches, the synthesis of nanoparticles (NPs) from plant extracts has gained extraordinary attention owing to its advantages of being eco-friendly, cost-effective, rapid, simple, and efficient. Furthermore, the extracts obtained from different sources and parts of the plant boast a rich content of bioactive molecules, which are mainly responsible for the fabrication of NPs with great potential in many applications. Recently, halophytes and salt-tolerant plants have been exploited as possible resources for the synthesis of nanomaterials. Species belonging to the Acanthaceae, Fabaceae, Lythraceae, and Malvaceae families have received more attention. Also, extracts derived from various parts of the plant, such as roots, stems, barks, leaves, flowers, fruits, and seeds, have been used to synthesize a wide range of metal and metal oxide NPs. The possibility of obtaining NPs with various shapes, sizes, structures, and chemical compositions by tuning the synthesis parameters is an additional advantage. Due to their unique physical, chemical, and biological properties, the nanoparticles synthesized using extracts derived from halophytes and other salt-tolerant plants have been exploited for several applications, including (photo)catalysis, sensing, and therapeutic agents. In addition, hybrid nanomaterials have emerged as powerful platforms for addressing infections, cancer, or environmental pollution. This chapter is a novelty because it encompasses a survey of the synthesis and properties of metal and metal oxide-based nanoparticles (NPs) using halophytes and other salt-tolerant plants, along with their potential applications in the fields of biology, environmental remediation, agriculture, and food technology.