User interface (UI) design significantly impacts user experience (UX) by determining how users interact with a digital product. A well-designed UI ensures that interactions are intuitive, reducing the learning curve and enhancing user satisfaction. Key elements include layout, visual elements, and responsiveness, all of which guide users through the application or website, helping them accomplish tasks efficiently. If the UI is cluttered or confusing, users may become frustrated and abandon the product. Conversely, an effective UI encourages engagement and improves user retention by making navigation seamless, ultimately contributing to a positive overall experience.