Some popular programming languages for developing GUIs (Graphical User Interfaces) include:

1. Java: Used for developing desktop applications, Android apps, and web applications.

2. Python: Used with libraries like Tkinter, PyQt, and wxPython for desktop applications.

3. C++: Used for developing high-performance applications, games, and system software.

4. C#: Used for developing Windows desktop and mobile applications.

5. JavaScript: Used for developing web applications and desktop applications with Electron.

6. Swift: Used for developing macOS and iOS applications.

7. Kotlin: Used for developing Android applications.

8. Ruby: Used with libraries like Ruby-GNUPLOT and Shoes for desktop applications.

9. PHP: Used for developing web applications with libraries like PHP-GTK.

10. Visual Basic .NET ((link unavailable)): Used for developing Windows desktop applications.

Additionally, various frameworks and libraries like:

- Qt (C++ and others)

- wxWidgets (C++ and others)

- GTK+ (C and others)

- Electron (JavaScript)

- Flutter (Dart)

are also popular for GUI development, as they provide pre-built components, tools, and APIs to simplify the process.