Understanding this WP Theme Development Course

This is an brief introduction to the core concepts of WordPress theme development. We’ve worked hard over the years to write some of the best tutorials on WordPress development, and give them away to readers here at Lazycoders. Up and Running is our effort to consolidate all that teaching into a single step-by-step resource. Hopefully, it’s also a little easier to navigate than the mess of links that is this (or any) modern website. While the course is much more exhaustive on both WordPress theme and plugin development than this is, we’re sure this will give you a very solid foundation to start from. The three important concepts of WordPress theme development we’ll cover here are:

  1. The WordPress Template Hierarchy
  2. Processing Posts with The Loop
  3. Adding Functionality with functions.php

Core Concept 1 of WordPress Theme Development: The Template Hierarchy

The first thing that’ll help you get a sense of WordPress theme development is getting a sense of what all those theme files do. Some of them may be obvious to someone who has done a fair amount of web development, like style.css being the place for your CSS styling rules. But most the work you do in WordPress theme development comes down to understanding the WordPress template hierarchy. WordPress template hierarchy underlies a lot of what’s useful and complicated about WordPress. WordPress themes involve a bunch files. And understanding those files is the key to understanding WordPress development. All the files in the template hierarchy have a few things in common:
  • They have names that end with .php
  • They contain a version of “the Loop” inside of them (see the next section for more about that)
  • They mostly contain HTML and some PHP code

Those three bullet points are the core of what makes up the WordPress hierarchy. But there’s a lot more to understand. And that’s what our article all about it tries to help you with. Reading it will get you along the way to being a full-fledged WordPress theme developer:

Core Concept 2 of WordPress Theme Development: The Loop in WordPress and What it Means

For this one, we’ve taken the time to create a custom post. The Loop is one of the things that first scared me about WordPress development. The core thing was that it all sounded so ominous. Whether people called it “WordPress loop” of “The Loop”, I knew that WordPress had that complicated concept involved.

Later, after I’d programmed more, I realized that this was just a basic “while” loop, a common construct in almost all programs. But before that, it really intimidated me. If you feel like you’ve got it from that description alone, you might not need to read our full article about what the WordPress Loop is and what it means. Other than the syntax which is distinct to WordPress, it’s not much more complicated than that.

But if you’ve never done much coding, you probably should be sure to read the whole article. WordPress theme development is really dependent on getting a handle on how “the Loop” works in WordPress. You’ll hear people talk a lot, as you get into theming, about being “inside the WordPress loop” and outside of it. The article covers all of that and more. If you’ve not read it yet, please do:

Core Concept 3 of WordPress Theme Development: Adding Functionality with functions.php

Plugins are a big topic in WordPress, and I’ve sometimes heard people describe this next focus as “the plugin of a WordPress theme.” I don’t necessarily agree with that description. I also think it actually add confusion to the issue. That said, inside of your WordPress theme’s functions.php is indeed where you write all the relevant PHP functions that you’re going to want your theme to load into WordPress on every page load. That’s exactly how it’s similar to plugin. But unlike a plugin, you can’t just turn off a WordPress theme’s functions.php file.


There is one complicated wrinkle to how functions.php fits into WordPress. And it comes down to WordPress hooks. For both really understanding both WordPress theme development (and plugins) you must get to the bottom of that. For most people, that’s the hard part about a WordPress theme’s functions file.

Other than that, the other hard thing is PHP syntax itself. But you may already have mastered that yourself, of you can follow along on the next article and it’ll help make it a little clearer for you.