scikit-learn is an open-source machine learning library for the Python programming language. It provides simple and efficient tools for data analysis and modeling, making it accessible for both beginners and experienced users. The library supports various supervised and unsupervised learning algorithms, including classification, regression, and clustering. One of the key features of scikit-learn is its user-friendly interface, which allows users to easily implement machine learning models with just a few lines of code. It also integrates well with other scientific libraries in Python, such as NumPy and Pandas, enhancing its functionality for data manipulation and analysis.