ADO, or ActiveX Data Objects, is a Microsoft technology that allows developers to access and manipulate data from various sources, such as databases and spreadsheets. It provides a set of COM (Component Object Model) objects that simplify the process of connecting to data sources, executing commands, and retrieving results. Using ADO, developers can write applications in languages like VBScript or C# to interact with databases like SQL Server or Oracle. ADO supports various data operations, including querying, updating, and deleting records, making it a versatile tool for data-driven applications.