The three main languages used in Frontend Development are HTML, CSS, and JavaScript. HTML (HyperText Markup Language) is the language used to define the structure of a web page. It is used to create the basic elements of a page, such as headings, paragraphs, lists, and images. CSS (Cascading Style Sheets) is the language used to style a web page. It is used to control the appearance of the page, such as the colors, fonts, and margins of the elements. JavaScript is the language used to add interactivity to a web page. It is used to create animations, forms, and other dynamic elements.