The growth, development, and production of plants are severely hampered by abiotic conditions such as drought, salinity, high temperatures, and heavy metal toxicity. Reactive oxygen species (ROS) are produced in excess as a result of these stressors, which damages biomolecules and cellular structures oxidatively. Plants have developed complex antioxidant systems that include nonenzymatic antioxidants such as ascorbate, glutathione, carotenoids, and phenolic substances, as well as enzymatic antioxidants like superoxide dismutase (SOD), catalase (CAT), and peroxidases (POD). Secondary metabolites, such as flavonoids, alkaloids, and terpenoids, are essential for reducing oxidative stress and boosting plant resistance in addition to these antioxidant defenses. The complex interactions between secondary metabolism and antioxidant responses in plants under abiotic stress are examined in this review. Secondary metabolites' dual function as signaling molecules and ROS scavengers is examined, with a focus on how they support stress adaptation and redox equilibrium. Additionally, the way that ROS and antioxidants control the formation of secondary metabolites is investigated, providing insight into the dynamic feedback processes at play. Recent developments in molecular biology and omics technologies have demonstrated that transcription factors and signaling networks, including the MYB, bHLH, and WRKY families, as well as hormonal cross-talk involving abscisic acid, salicylic acid, and jasmonic acid, co-regulate antioxidant and secondary metabolic pathways. This study also emphasizes how biotechnological methods, such as genetic engineering and the use of exogenous elicitors, can be used to enhance plant stress tolerance by utilizing the integration of secondary metabolic pathways and antioxidants. Gaining insight into how these two systems work together offers encouraging opportunities to improve agricultural sustainability in the face of changing climate circumstances and create stress-resilient crops.