diff --git a/meta/lib/patchtest/patchtest_patterns.py b/meta/lib/patchtest/patchtest_patterns.py
index 1a8db92aa5..b3478d2f0f 100644
--- a/meta/lib/patchtest/patchtest_patterns.py
+++ b/meta/lib/patchtest/patchtest_patterns.py
@@ -57,6 +57,7 @@ invalid_submitters = [pyparsing.Regex("^Upgrade Helper.+"),
 mbox_bugzilla = pyparsing.Regex(r'\[\s?YOCTO.*\]')
 mbox_bugzilla_validation = pyparsing.Regex(r'\[(\s?YOCTO\s?#\s?(\d+)\s?,?)+\]')
 mbox_revert_shortlog_regex = pyparsing.Regex(r'Revert\s+".*"')
+mbox_cover_letter_regex = pyparsing.Regex(r'\[\S+\s+0+/\d+\]')
 mbox_shortlog_maxlength = 90
 # based on https://stackoverflow.com/questions/30281026/regex-parsing-github-usernames-javascript
 mbox_github_username = pyparsing.Regex(r'\B(?<!\${)@([a-z0-9](?:-(?=[a-z0-9])|[a-z0-9]){0,38}(?<=[a-z0-9]))')
diff --git a/meta/lib/patchtest/tests/test_mbox.py b/meta/lib/patchtest/tests/test_mbox.py
index a216028250..d465b58ba6 100644
--- a/meta/lib/patchtest/tests/test_mbox.py
+++ b/meta/lib/patchtest/tests/test_mbox.py
@@ -38,6 +38,9 @@ class TestMbox(base.Base):
             # skip those patches that revert older commits, these do not required the tag presence
             if patchtest_patterns.mbox_revert_shortlog_regex.search_string(commit.shortlog):
                 continue
+            # cover letters (00/N) are not commits and do not need Signed-off-by
+            if patchtest_patterns.mbox_cover_letter_regex.search_string(commit.subject):
+                continue
             if not patchtest_patterns.signed_off_by.search_string(commit.payload):
                 self.fail(
                     'Mbox is missing Signed-off-by. Add it manually or with "git commit --amend -s"',
@@ -53,6 +56,9 @@ class TestMbox(base.Base):
                 # no reason to re-check on revert shortlogs
                 if shortlog.startswith('Revert "'):
                     continue
+                # cover letters (00/N) have series titles, not target: summary format
+                if patchtest_patterns.mbox_cover_letter_regex.search_string(commit.subject):
+                    continue
                 try:
                     patchtest_patterns.shortlog.parseString(shortlog)
                 except pyparsing.ParseException as pe: