diff --git a/patchwork/forge/__init__.py b/patchwork/forge/__init__.py
index cadca53..79a1366 100644
--- a/patchwork/forge/__init__.py
+++ b/patchwork/forge/__init__.py
@@ -28,6 +28,7 @@ from dataclasses import field
 
 from django.conf import settings
 from django.db import transaction
+from django.db.models.signals import post_save
 
 from patchwork.models import Event
 from patchwork.models import ForgeConfig
@@ -180,6 +181,16 @@ class ForgeBackend(ABC):
         """
         raise NotImplementedError
 
+    @abstractmethod
+    def handle_comment_created(self, forge_config, comment, series):
+        """
+        Handle a comment on a patch or cover letter.
+
+        Called by the comment-created signal handler. The backend
+        decides whether to forward the comment to the forge PR.
+        """
+        raise NotImplementedError
+
 
 _backends = {}
 
@@ -217,12 +228,46 @@ def _on_series_completed(sender, instance, raw, **kwargs):
     transaction.on_commit(do_sync)
 
 
-def load_backends():
-    from django.db.models.signals import post_save
+def _on_comment_created(sender, instance, raw, **kwargs):
+    if raw:
+        return
+
+    if instance.category == Event.CATEGORY_PATCH_COMMENT_CREATED:
+        comment = instance.patch_comment
+        if not comment:
+            return
+        series = comment.patch.series
+    elif instance.category == Event.CATEGORY_COVER_COMMENT_CREATED:
+        comment = instance.cover_comment
+        if not comment:
+            return
+        series = comment.cover.series
+    else:
+        return
+
+    if not series:
+        return
+
+    def do_sync():
+        for forge_config in ForgeConfig.objects.filter(project=series.project):
+            backend = get_backend(forge_config.backend)
+            if not backend:
+                continue
+            try:
+                backend.handle_comment_created(forge_config, comment, series)
+            except Exception:
+                logger.exception(
+                    'forge comment sync failed for series %d on %s',
+                    series.id,
+                    forge_config.backend,
+                )
+
+    transaction.on_commit(do_sync)
 
-    from patchwork.models import Event
 
+def load_backends():
     for module_path in settings.FORGE_BACKENDS:
         importlib.import_module(module_path)
 
     post_save.connect(_on_series_completed, sender=Event)
+    post_save.connect(_on_comment_created, sender=Event)
diff --git a/patchwork/forge/github/__init__.py b/patchwork/forge/github/__init__.py
index b2dbf23..18200a4 100644
--- a/patchwork/forge/github/__init__.py
+++ b/patchwork/forge/github/__init__.py
@@ -15,6 +15,7 @@ import logging
 from patchwork.forge import ForgeBackend
 from patchwork.forge import register_backend
 from patchwork.forge.github.from_ml import create_or_update_pr
+from patchwork.forge.github.from_ml import post_pr_comment
 from patchwork.forge.github.to_ml import handle_check_pending
 from patchwork.forge.github.to_ml import handle_check_result
 from patchwork.forge.github.to_ml import handle_issue_comment
@@ -99,5 +100,8 @@ class GitHubBackend(ForgeBackend):
     def handle_series_completed(self, forge_config, series):
         create_or_update_pr(self, forge_config, series)
 
+    def handle_comment_created(self, forge_config, comment, series):
+        post_pr_comment(self, forge_config, comment, series)
+
 
 register_backend('github', GitHubBackend())
diff --git a/patchwork/forge/github/api.py b/patchwork/forge/github/api.py
index d2332a7..92b4a73 100644
--- a/patchwork/forge/github/api.py
+++ b/patchwork/forge/github/api.py
@@ -11,6 +11,7 @@ import urllib.request
 
 from patchwork.forge import CheckRun
 from patchwork.forge import ReviewComment
+from patchwork.forge.util import COMMENT_MARKER
 
 logger = logging.getLogger(__name__)
 
@@ -55,7 +56,7 @@ def fetch_review_comments(gh, forge_config, pr_number, review_id):
     comments = []
     for r in results:
         body = r.get('body') or ''
-        if body == '':
+        if body == '' or COMMENT_MARKER in body:
             continue
         comments.append(
             ReviewComment(
diff --git a/patchwork/forge/github/from_ml.py b/patchwork/forge/github/from_ml.py
index ccb44c8..4b1acf4 100644
--- a/patchwork/forge/github/from_ml.py
+++ b/patchwork/forge/github/from_ml.py
@@ -4,12 +4,14 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
 
+import email
 import logging
 
 from patchwork.forge.git import GitMirror
 from patchwork.forge.github.api import base_branch
 from patchwork.forge.github.api import create_pr
 from patchwork.forge.github.api import post_comment
+from patchwork.forge.util import COMMENT_MARKER
 from patchwork.forge.util import build_pr_body
 from patchwork.forge.util import forge_branch_name
 from patchwork.forge.util import series_from_forge
@@ -106,3 +108,26 @@ def store_series_metadata(gh, forge_config, series, pr_ref, branch):
         key=f'{forge_config.backend}_branch',
         defaults={'value': branch},
     )
+
+
+def post_pr_comment(gh, forge_config, comment, series):
+    if not forge_config.sync_ml_to_forge:
+        return
+
+    if comment.headers:
+        parsed = email.message_from_string(comment.headers)
+        hint = parsed.get('X-Patchwork-Hint', '')
+        if hint.lower() == 'ignore':
+            return
+
+    pr_meta = SeriesMetadata.objects.filter(
+        series=series, key=gh.meta_key_pr()
+    ).first()
+    if not pr_meta:
+        return
+
+    pr_number = int(pr_meta.value.rsplit('/', 1)[-1])
+    author = comment.submitter.name or comment.submitter.email
+    quoted = '\n'.join(f'> {line}' for line in comment.content.splitlines())
+    body = f'**{author}** commented:\n\n{quoted}\n\n{COMMENT_MARKER}'
+    post_comment(gh, forge_config, pr_number, body)