The role of neural networks in machine learning is to simulate the way human brains process information through interconnected nodes or neurons. These networks excel at recognizing patterns and making predictions based on input data. By adjusting the weights of connections during training, neural networks can learn complex functions and improve accuracy over time. They are essential in various applications, including image recognition, natural language processing, and recommendation systems. As technology advances, neural networks continue to transform industries, offering powerful tools for data analysis and decision-making.