Free WordPress.com hosted sites
Sketchfab model embeds are natively supported (via our oEmbed endpoint). Simply drop a model URL in your WordPress post and it will become an embedded model. See the WordPress Support page for more details.
Check out this example.
WordPress.org powered sites
We made a WordPress plugin that lets you easily embed any Sketchfab model on WordPress. It adds a little button to the post editor asking for the id of the model. Then you can embed it directly on your blog. You can download the WordPress plugin here.
You can also use a shortcode in your blogpost to embed Sketchfab models like this:
The model ID is the 32-character string in the model's URL, e.g. "442c548d94744641ba279ae94b5f45ec"
[sketchfab id="the_model_id" start="0" spin="" controls="0" transparent="0"]
Note for free wordpress.com users: you can’t use this plugin as WordPress disabled plugins as well as the iframe tag on their servers.
Rami Yushuvaev has also created a WordPress plugin that adds Sketchfab to your oEmbed providers. You can find it here.