diff --git a/CHANGES b/CHANGES
index 0c6f70d10..9608e3aa3 100644
--- a/CHANGES
+++ b/CHANGES
@@ -35,6 +35,7 @@ Bugs fixed
 * #6172: AttributeError is raised for old styled index nodes
 * #4872: inheritance_diagram: correctly describe behavior of ``parts`` option in
   docs, allow negative values.
+* #6178: i18n: Captions missing in translations for hidden TOCs
 
 Testing
 --------
diff --git a/sphinx/builders/gettext.py b/sphinx/builders/gettext.py
index aace9bb49..092d64e2d 100644
--- a/sphinx/builders/gettext.py
+++ b/sphinx/builders/gettext.py
@@ -16,6 +16,7 @@ from os import path, walk, getenv
 from time import time
 from uuid import uuid4
 
+from sphinx import addnodes
 from sphinx.builders import Builder
 from sphinx.domains.python import pairindextypes
 from sphinx.errors import ThemeError
@@ -142,6 +143,11 @@ class I18nBuilder(Builder):
         # type: (str, nodes.document) -> None
         catalog = self.catalogs[find_catalog(docname, self.config.gettext_compact)]
 
+        for toctree in self.env.tocs[docname].traverse(addnodes.toctree):
+            for node, msg in extract_messages(toctree):
+                node.uid = ''  # type: ignore  # Hack UUID model
+                catalog.add(msg, node)
+
         for node, msg in extract_messages(doctree):
             catalog.add(msg, node)
 
diff --git a/tests/roots/test-intl/index.po b/tests/roots/test-intl/index.po
index 76ef049f0..a4646f1ec 100644
--- a/tests/roots/test-intl/index.po
+++ b/tests/roots/test-intl/index.po
@@ -19,6 +19,9 @@ msgstr ""
 msgid "Table of Contents"
 msgstr "TABLE OF CONTENTS"
 
+msgid "Hidden Toc"
+msgstr "HIDDEN TOC"
+
 msgid "testdata for i18n"
 msgstr "TESTDATA FOR I18N"
 
diff --git a/tests/roots/test-intl/index.txt b/tests/roots/test-intl/index.txt
index cd63b5ec3..1e09294f9 100644
--- a/tests/roots/test-intl/index.txt
+++ b/tests/roots/test-intl/index.txt
@@ -30,3 +30,10 @@ CONTENTS
    refs
    section
    topic
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Hidden Toc
+   :hidden:
+
+   only
diff --git a/tests/test_intl.py b/tests/test_intl.py
index 35e8f6909..803e22a0f 100644
--- a/tests/test_intl.py
+++ b/tests/test_intl.py
@@ -617,6 +617,8 @@ def test_html_meta(app):
     assert expected_expr in result
     expected_expr = '<meta content="I18N, SPHINX, MARKUP" name="keywords" />'
     assert expected_expr in result
+    expected_expr = '<p class="caption"><span class="caption-text">HIDDEN TOC</span></p>'
+    assert expected_expr in result
 
 
 @sphinx_intl