A theme is a slide design made up of cohesive colors, fonts, and effects such as shadows or reflections. A template includes a theme, but also contains instructions in placeholders suggesting what to insert and what types of information the user of the template might want to include.

Themes provide your presentations with a designer-quality appearance. It includes one or more slide layouts with synchronizing colors, fonts, effects, and matching backgrounds. While on the other hand, a PowerPoint template is a blueprint or pattern of a slide or a collection of slides that are saved as a.potx file.

Technically speaking, a template just has the default action of creating a new presentation with all the content stored inside it instead of opening as a presentation that you can edit. A PowerPoint theme is a little more nuanced. A theme is a collection of colors, effects, backgrounds, and fonts that can be applied to any presentation.

A template is a theme plus some content for a specific purpose—such as a sales presentation, a business plan, or a classroom lesson. So a template has design elements that work together (colors, fonts, backgrounds, effects) along with sample slides and boilerplate content that you augment to tell your story.