I'm not on Windows at the moment, but from memory, you put a file called `.gtkrc-2.0` in your `%UserProfile%` directory (ie. `C:\Users\you.gtkrc-2.0`) and inside that file, put a line like:

``` gtk-theme-name = "YourThemeHere" ```

JFTR: beginning with Geany 1.38, the Windows builds use GTK3 and here is what is needed:

Create or edit the file `C:\Users<username>AppData\Local\gtk-3.0\settings.ini` with the following content: ```ini [Settings] gtk-theme-name=Windows10 ```

And your theme files should be located in `C:\Users<username>\AppData\Local\themes\Windows10`. Replace "<username>" with your username and "Windows10" with the theme you want to use.