Plants possess a remarkable capacity to synthesize a diverse array of secondary metabolites, encompassing antioxidants, pigments, flavors, and pharmaceuticals, crucial for their survival and interaction with the environment. However, the inherent limitations in natural production quantities have spurred exploration into cell and organ cultures as viable alternatives for large-scale production. Efficient production of these bioactive compounds in vitro presents a complex challenge influenced by numerous factors. This chapter meticulously explores the multifaceted aspects impacting the accumulation of secondary metabolites in cultured plant cells and hairy roots. Key factors discussed include the selection of optimal explant sources, the impact of culture vessel types on growth dynamics, the pivotal role of nutrient composition in media formulations, and the strategic use of plant growth regulators. Furthermore, environmental variables and their profound effects on metabolite synthesis are examined. By comprehensively dissecting these factors, this chapter aims to equip researchers and practitioners with insights and strategies to maximize both the yield and quality of bioactive compounds in plant tissue cultures. The integration of these findings not only advances scientific understanding but also enhances the practical applications of plant biotechnology in pharmaceutical, agricultural, and industrial sectors.