Oxidative stress is a key modulator in neurodegenerative diseases. This review discusses the role of oxidative stress (OS) in neurodegenerative disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). Oxidative stress arises from an imbalance between oxidants and antioxidants, leading to the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). These species can damage biomolecules such as DNA, lipids, and proteins, causing cellular dysfunction and neurodegeneration. Mitochondria play a central role in ROS production and oxidative stress, as they are involved in ATP synthesis and redox metabolism. ROS can cause mitochondrial dysfunction, leading to cell death and neurodegeneration. The brain is particularly vulnerable to oxidative stress due to its high oxygen consumption and lipid content, making it prone to ROS-induced damage. Neurodegenerative diseases are associated with oxidative stress, and various factors such as metal toxicity, protein misfolding, and inflammation contribute to this process. Antioxidants and antioxidant enzymes help combat oxidative stress, but their effectiveness is limited by the blood-brain barrier. Research is ongoing to develop new therapies targeting oxidative stress in neurodegenerative diseases. The review highlights the importance of understanding the mechanisms of oxidative stress in neurodegenerative diseases and the need for effective treatments to combat these conditions.Oxidative stress is a key modulator in neurodegenerative diseases. This review discusses the role of oxidative stress (OS) in neurodegenerative disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). Oxidative stress arises from an imbalance between oxidants and antioxidants, leading to the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). These species can damage biomolecules such as DNA, lipids, and proteins, causing cellular dysfunction and neurodegeneration. Mitochondria play a central role in ROS production and oxidative stress, as they are involved in ATP synthesis and redox metabolism. ROS can cause mitochondrial dysfunction, leading to cell death and neurodegeneration. The brain is particularly vulnerable to oxidative stress due to its high oxygen consumption and lipid content, making it prone to ROS-induced damage. Neurodegenerative diseases are associated with oxidative stress, and various factors such as metal toxicity, protein misfolding, and inflammation contribute to this process. Antioxidants and antioxidant enzymes help combat oxidative stress, but their effectiveness is limited by the blood-brain barrier. Research is ongoing to develop new therapies targeting oxidative stress in neurodegenerative diseases. The review highlights the importance of understanding the mechanisms of oxidative stress in neurodegenerative diseases and the need for effective treatments to combat these conditions.