Render an entity reference in a twig template I have a field that is an entity reference. I would like to print the entire entity in my controller. 

I know I can print a particular field of the entity using something like

{{ teacher.field_classrooms.entity.field_classroom_one.value }}


but I need to print the whole entity rather than just one field.

How can I accomplish this?
first you should select show Rendered Entity in your content type field Manage Display section in admin/structure/types/manage/teacher/display (I supposed your content type is teacher based on your question), then in your node template  try to render the content field with something like 

{{ content.field_classrooms }}