diff --git a/changelogs/fragments/41530-apt-mark-deb6.yaml b/changelogs/fragments/41530-apt-mark-deb6.yaml
new file mode 100644
index 00000000000..43ab5c57f26
--- /dev/null
+++ b/changelogs/fragments/41530-apt-mark-deb6.yaml
@@ -0,0 +1,2 @@
+bugfixes:
+  - apt: fix apt-mark on debian6 (https://github.com/ansible/ansible/pull/41530)
diff --git a/lib/ansible/modules/packaging/os/apt.py b/lib/ansible/modules/packaging/os/apt.py
index cd0d99dc5c4..9c06d0347d8 100644
--- a/lib/ansible/modules/packaging/os/apt.py
+++ b/lib/ansible/modules/packaging/os/apt.py
@@ -275,6 +275,7 @@ APTITUDE_ZERO = "\n0 packages upgraded, 0 newly installed"
 APT_LISTS_PATH = "/var/lib/apt/lists"
 APT_UPDATE_SUCCESS_STAMP_PATH = "/var/lib/apt/periodic/update-success-stamp"
 APT_MARK_INVALID_OP = 'Invalid operation'
+APT_MARK_INVALID_OP_DEB6 = 'Usage: apt-mark [options] {markauto|unmarkauto} packages'
 
 HAS_PYTHON_APT = True
 try:
@@ -483,7 +484,7 @@ def mark_installed_manually(m, packages):
     cmd = "%s manual %s" % (apt_mark_cmd_path, ' '.join(packages))
     rc, out, err = m.run_command(cmd)
 
-    if APT_MARK_INVALID_OP in err:
+    if APT_MARK_INVALID_OP in err or APT_MARK_INVALID_OP_DEB6 in err:
         cmd = "%s unmarkauto %s" % (apt_mark_cmd_path, ' '.join(packages))
         rc, out, err = m.run_command(cmd)