HTML stands for Hyper Text Markup Language and is the standardized programming language for websites worldwide. It is non-dynamic, meaning that without any other languages on the same page, a HTML-based page is completely static – it does not interact with databases and it cannot return different information from the same physical file.
If you are planning on designing and developing your site yourself, then it is almost certain that you will need at least some HTML knowledge, if not learn it.
Even if your page is PHP based, for example, HTML code will almost certainly still exist in that page since PHP itself does not output anything for a browser to read.