A/B Testing is a method used to compare two versions of a webpage, app, or other product feature to determine which one performs better in terms of a specific goal, such as increasing conversion rates, user engagement, or sales. It involves showing one version (A) to one group of users and a different version (B) to another group, and then analyzing the performance of each version based on predefined metrics. The version that performs better is considered the more effective option. A/B Testing is commonly used in marketing, product development, and UX/UI design to make data-driven decisions.