Bootstrap 3 Navbar dropdown problem
If i'm understanding this correctly, it looks like you just have your loop starting a little early in the markup, so at the moment you are creating a new &lt;ul class="nav navbar-nav"&gt; item for every entry.

Does moving the {% nav entry in entries %} loop within the first &lt;ul&gt; help at all? like this:

&lt;ul class="nav navbar-nav"&gt;
 {% nav entry in entries %}
     &lt;li&gt;
        &lt;a href="{{ entry.url }}"&gt;{{ entry.title }}&lt;/a&gt;
        {% ifchildren %}
           &lt;li class="dropdown"&gt;
             &lt;a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false"&gt;&lt;span class="caret"&gt;&lt;/span&gt;&lt;/a&gt;
              &lt;ul class="dropdown-menu"&gt;
               {% children %}
              &lt;/ul&gt;
           &lt;/li&gt;
        {% endifchildren %}
     &lt;/li&gt;
 {% endnav %}
&lt;/ul&gt;


Additionally

Whilst writing this answer out I noticed that your {% endifchildren %} tag comes before a closing &lt;/li&gt; tag, so it might just be that:

&lt;ul class="nav navbar-nav"&gt;
  &lt;li&gt;
     &lt;a href="{{ entry.url }}"&gt;{{ entry.title }}&lt;/a&gt;
     {% ifchildren %}
       &lt;li class="dropdown"&gt;
         &lt;a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false"&gt;&lt;span class="caret"&gt;&lt;/span&gt;&lt;/a&gt;
           &lt;ul class="dropdown-menu"&gt;
              {% children %}
           &lt;/ul&gt;
          {# endifchildren was originally here #}
        &lt;/li&gt;
     {% endifchildren %}
  &lt;/li&gt;
&lt;/ul&gt;