If you have SCSS and Emmet plugins installed in Sublime Text but tab autocompletion (ex. dib -> display: inline-block) doesn’t work then a solution to make it work is to update the css_completions_scope Emmet config value.

1. Find the completion scope of SCSS code

In order to find the completion scope place the cursor in Sublime right after the text you want to autocomplete/expand. Then press Shift+Ctrl+P and check what’s the current scope in Sublime status bar (footer) In my case it was source.scss meta.property-list.scss

2. Get default Emmet CSS completion scope settings

In sublime open default Emmet plugin settings: Preferences -> Package Settings -> Emmet -> Settings - Default and find the css_completions_scope option. In my case it was

// List of scopes where Emmet CSS completions should be available
"css_completions_scope": "source.css - meta.selector.css - meta.property-value.css, source.scss - meta.selector.scss - meta.property-value.scss, source.less - meta.selector.css - meta.property-value.css",

3. Update Emmet CSS completion scope settings

Now we can update the css_completions_scope by adding the scope that we found earlier. For this open Preferences -> Package Settings -> Emmet -> Settings - User and add new scope to the list of completions scope:

{
  "css_completions_scope": "source.css - meta.selector.css - meta.property-value.css, source.scss - meta.selector.scss - meta.property-value.scss - meta.poperty-list.css, source.less - meta.selector.css - meta.property-value.css, source.scss - meta.poperty-list.scss",
}

Now Emmet expanding should work as expected.