Fuzzing is a software testing technique used to identify vulnerabilities and bugs in programs. It involves sending random or unexpected data, known as "fuzz," to a program to see how it responds. By observing the program's behavior, testers can discover weaknesses that could be exploited by attackers. This method is particularly useful for testing applications, such as web browsers or operating systems, where security is crucial. Fuzzing helps developers improve the reliability and safety of their software by uncovering issues that might not be found through traditional testing methods.