Visual Basic (VB) is an event driven programming language and associated development environment prototyped by Alan Cooper as Project Ruby, then bought and vastly improved upon by Microsoft. VB has been replaced by Visual Basic .NET. The older version of VB was derived heavily from BASIC and enables rapid application development (RAD) of graphical user interface (GUI) applications, access to databases using DAO, RDO, or ADO, and creation of ActiveX controls and objects.

A programmer can put together an application using the components provided with Visual Basic itself. Programs written in Visual Basic can also use the Windows API, but doing so requires external function declarations. In business programming, Visual Basic has one of the largest user bases. According to some sources, as of 2003, 52 percent of software developers used Visual Basic, making it the most popular programming language at that time. However, research done by Evans Data found that forty three percent of those Visual Basic developers planned to move to other languages.

Visual Basic was designed to be easy to learn and use. The language not only allows programmers to easily create simple GUI applications, but also has the flexibility to develop fairly complex applications as well.

Programming in VB is a combination of visually arranging components or controls on a form, specifying attributes and actions of those components, and writing additional lines of code for more functionality. Since default attributes and actions are defined for the components, a simple program can be created without the programmer having to write many lines of code.

Performance problems were experienced by earlier versions, but with faster computers and native code compilation this has become less of an issue. Although programs can be compiled into native code executables from version 5 onwards, they still require the presence of runtime libraries of approximately 2 MB in size. This runtime is included by default in Windows 2000 and later, but for earlier versions of Windows it must be distributed together with the executable.

Forms are created using drag and drop techniques. A tools palette is used to place controls (e.g., text boxes, buttons, etc.) on the form (window). Controls have attributes and event handlers associated with them. Default values are provided when the control is created, but may be changed by the programmer.

Many attribute values can be modified during run time based on user actions or changes in the environment, providing a dynamic application.

For example, code can be inserted into the form resize event handler to reposition a control so that it remains centered on the form, expands to fill up the form, etc. By inserting code into the event handler for a keypress in a text box, the program can automatically translate the case of the text being entered, or even prevent certain characters from being inserted.