Streptomycetes are a diverse group of filamentous, Gram-positive actinobacteria, that have been emerged as promising plant growth-promoting microorganisms either by directly enhancing plant growth or by protecting crops from pathogens. In the rhizosphere, Streptomyces species promote beneficial symbiotic relationships that improve soil health and enhance nutrient uptake. Further, these bacteria are known for their ability to synthesize a wide variety of bioactive compounds through secondary metabolism. By fixing nitrogen, solubilizing phosphates, producing siderophores and synthesizing phytohormones, these actinobacteria contribute to plant health. Approximately one third of all antimicrobial compounds have been reported from Streptomyces species. This capability of Streptomyces spp. has attracted considerable attention from researchers seeking solutions for sustainable agriculture. Streptomyces have been reported to increase crop resistance to biotic and abiotic stressors, thereby lowering the need for chemical inputs. When Streptomyces are used as biofertilizers and biopesticides, they promote environment friendly farming practices while improving crop production and quality. However, the challenges such as the selection of highly efficient strains, optimization for large-scale production and their stability and efficacy under diverse field conditions continue to limit their widespread application. This chapter aims to provide an overview of Streptomyces in light of their potential as plant growth-promoting bacteria (PGPBs), their secondary metabolism, plant interactions and underlying molecular mechanisms.