TensorFlow is a popular open-source machine learning framework developed by Google. It allows users to define and train neural networks and other machine learning models. TensorFlow represents all data in the form of multidimensional arrays called tensors that flow through its computational graph. It supports a variety of machine learning tasks including image recognition, natural language processing, and time series forecasting. TensorFlow provides features like scalability across multiple CPUs and GPUs, model visualization tools, and an active developer community.