diff --git a/django/contrib/admin/templates/admin/includes/fieldset.html b/django/contrib/admin/templates/admin/includes/fieldset.html
index 09bc971d2f..24b069cb2f 100644
--- a/django/contrib/admin/templates/admin/includes/fieldset.html
+++ b/django/contrib/admin/templates/admin/includes/fieldset.html
@@ -7,7 +7,7 @@
         <div class="form-row{% if line.fields|length_is:'1' and line.errors %} errors{% endif %}{% for field in line %}{% if field.field.name %} field-{{ field.field.name }}{% endif %}{% endfor %}">
             {% if line.fields|length_is:'1' %}{{ line.errors }}{% endif %}
             {% for field in line %}
-                <div{% if not line.fields|length_is:'1' %} class="field-box{% if field.field.name %} field-{{ field.field.name }}{% endif %}{% if not field.is_readonly and field.errors %} errors{% endif %}"{% endif %}>
+                <div{% if not line.fields|length_is:'1' %} class="field-box{% if field.field.name %} field-{{ field.field.name }}{% endif %}{% if not field.is_readonly and field.errors %} errors{% endif %}"{% elif field.is_checkbox %} class="checkbox-row"{% endif %}>
                     {% if not line.fields|length_is:'1' and not field.is_readonly %}{{ field.errors }}{% endif %}
                     {% if field.is_checkbox %}
                         {{ field.field }}{{ field.label_tag }}