Before you start learning React, it's important to have a solid understanding of JavaScript, as React is a JavaScript library. You should be comfortable with concepts like ES6 features, closures, asynchronous programming, and this keyword. HTML and CSS knowledge is also essential as you'll be working with JSX, which is a syntax extension for JavaScript that resembles HTML. Familiarity with Node.js and npm (Node Package Manager) is also beneficial as they are often used in React development for package management and executing scripts.