X-Frame-Options is a security header used in web development to prevent clickjacking attacks. Clickjacking occurs when a malicious site tricks users into clicking on something different from what they perceive, potentially leading to unauthorized actions. By implementing this header, a website can control whether its content can be embedded in an iframe on other sites. There are three main directives for X-Frame-Options: "DENY," which completely disallows framing; "SAMEORIGIN," which allows framing only from the same origin; and "ALLOW-FROM," which permits framing from specified origins. This helps enhance the security of web applications and protect user interactions.