While WordPress themes technically only require two files (index.php in classic themes and index.html in block themes, and style.css), they usually are made up of many files. That means they can quickly become disorganized! This section will show you how to keep your files organized.

Theme folder and file structure

As mentioned previously, the default Twenty themes are some of the best examples of good theme development. For instance, here is how the Twenty Seventeen Theme organizes its file structure:

.
├── assets (dir)/
│   ├── css (dir)
│   ├── images (dir)
│   └── js (dir)
├── inc (dir)
├── template-parts (dir)/
│   ├── footer (dir)
│   ├── header (dir)
│   ├── navigation (dir)
│   ├── page (dir)
│   └── post (dir)
├── 404.php
├── archive.php
├── comments.php
├── footer.php
├── front-page.php
├── functions.php
├── header.php
├── index.php
├── page.php
├── README.txt
├── rtl.css
├── screenshot.png
├── search.php
├── searchform.php
├── sidebar.php
├── single.php
└── style.css

You can see that the main theme template files are in the root directory, while JavaScript, CSS, images are placed in assets directory, template-parts are placed in under respective subdirectory of template-parts and collection of  functions related to core functionalities are placed in inc directory.

There are no required folders in classic themes. In block themes, templates must be placed inside a folder called templates, and all template parts must be placed inside a folder called parts.

Languages folder

It’s best practice to internationalize your theme so it can be translated into other languages. Default themes include the languages folder, which contains a .pot file for translation and any translated .mo files. While languages is the default name of this folder, you can change the name. If you do so, you must update <a href="https://developer.wordpress.org/reference/functions/load_theme_textdomain/">load_theme_textdomain()</a>.