You can remove a theme from your online store within the Themes page in your Shopify admin.
You can add up to 20 themes to your online store. If you already have 20 themes, then you can remove themes to make room for more.
Remove an unpublished theme
You can remove an unpublished theme from your admin. This is a permanent action.
- From your Shopify admin, go to Online Store > Themes.
- In the Theme library section, find the theme that you want to remove, click the
...button to open the actions menu, and then click Remove.
- On the Remove... window, click Remove.