Disabled

With Bootstrap Select disabled can be applied to a select, option, and optgroup

Disabled select

Disabled option and optgroup

<!-- Disabled select -->
<select class="selectpicker" disabled>
  <optgroup label="Picnic">
    <option>Mustard</option>
    <option>Ketchup</option>
    <option>Relish</option>
  </optgroup>
</select>

<!-- Disabled option and optgroup -->
<select class="selectpicker">
  <optgroup label="Picnic" disabled>
    <option>Mustard</option>
    <option>Ketchup</option>
    <option>Relish</option>
  </optgroup>
  <optgroup label="Camping">
    <option disabled="disabled">Tent</option>
    <option>Flashlight</option>
    <option>Toilet Paper</option>
  </optgroup>
</select>
wvusUikit(".selectpicker").selectpicker();