diff --git a/r2/r2/controllers/api.py b/r2/r2/controllers/api.py
index 496eeaaeb..2513f8595 100644
--- a/r2/r2/controllers/api.py
+++ b/r2/r2/controllers/api.py
@@ -1980,8 +1980,10 @@ class ApiController(RedditController):
                     not sr.should_ratelimit(c.user, 'comment')):
                 should_ratelimit = False
 
-            if link._age > sr.archive_age:
-                c.errors.add(errors.TOO_OLD, field = "parent")
+            if link.archived:
+                c.errors.add(errors.TOO_OLD, field="parent")
+            elif link.locked:
+                c.errors.add(errors.THREAD_LOCKED, field="parent")
 
             hooks.get_hook("comment.validate").call(sr=sr, link=link,
                            parent_comment=parent_comment)
@@ -1995,7 +1997,8 @@ class ApiController(RedditController):
                 commentform.has_errors("ratelimit", errors.RATELIMIT) or
                 commentform.has_errors("parent", errors.DELETED_COMMENT,
                     errors.DELETED_LINK, errors.TOO_OLD, errors.USER_BLOCKED,
-                    errors.USER_MUTED, errors.MUTED_FROM_SUBREDDIT)
+                    errors.USER_MUTED, errors.MUTED_FROM_SUBREDDIT,
+                    errors.THREAD_LOCKED)
         ):
             return
 
diff --git a/r2/r2/controllers/front.py b/r2/r2/controllers/front.py
index bef9f96c7..2049f6a87 100644
--- a/r2/r2/controllers/front.py
+++ b/r2/r2/controllers/front.py
@@ -357,7 +357,7 @@ class FrontController(RedditController):
         if c.user_is_loggedin and can_comment_link(article) and not is_api():
             #no comment box for permalinks
             display = False
-            if not comment and not article.archived:
+            if not comment and not article.archived and not article.locked:
                 display = True
 
             if article.promoted:
diff --git a/r2/r2/lib/errors.py b/r2/r2/lib/errors.py
index 38017d0db..206f951fd 100644
--- a/r2/r2/lib/errors.py
+++ b/r2/r2/lib/errors.py
@@ -113,6 +113,7 @@ error_list = dict((
         ('NO_SELFS', _("that subreddit doesn't allow text posts")),
         ('NO_LINKS', _("that subreddit only allows text posts")),
         ('TOO_OLD', _("that's a piece of history now; it's too late to reply to it")),
+        ('THREAD_LOCKED', _("Comments are locked.")),
         ('BAD_CSS_NAME', _('invalid css name')),
         ('BAD_CSS', _('invalid css')),
         ('BAD_COLOR', _('invalid color')),
diff --git a/r2/r2/lib/pages/pages.py b/r2/r2/lib/pages/pages.py
index d3d49a383..417e583c2 100644
--- a/r2/r2/lib/pages/pages.py
+++ b/r2/r2/lib/pages/pages.py
@@ -1869,7 +1869,7 @@ class CommentPane(Templated):
             # buttons and do the same for loggedout users so they can use the
             # same cached page. reply buttons will be hidden client side for
             # loggedout users
-            self.can_reply = article._age < article.subreddit_slow.archive_age
+            self.can_reply = not article.archived and not article.locked
 
         builder = CommentBuilder(
             article, sort, comment=comment, context=context, num=num, **kw)
diff --git a/r2/r2/models/link.py b/r2/r2/models/link.py
index df35cc9ac..2123fbb64 100644
--- a/r2/r2/models/link.py
+++ b/r2/r2/models/link.py
@@ -112,6 +112,7 @@ class Link(Thing, Printable):
                      managed_promo=False,
                      pending=False,
                      disable_comments=False,
+                     locked=False,
                      selftext='',
                      sendreplies=True,
                      ip='0.0.0.0',
@@ -1406,7 +1407,7 @@ class Comment(Thing, Printable):
             else:
                 item.parent_permalink = None
 
-            item.can_reply = item.link._age < item.subreddit.archive_age
+            item.can_reply = not item.link.archived and not item.link.locked
             if c.user_is_loggedin:
                 item.can_reply &= item.sr_id in can_reply_srs
 
diff --git a/r2/r2/templates/usertext.html b/r2/r2/templates/usertext.html
index 0b13bc1b0..7ff16999a 100644
--- a/r2/r2/templates/usertext.html
+++ b/r2/r2/templates/usertext.html
@@ -159,6 +159,7 @@
           ${error_field("RATELIMIT", "ratelimit", "span")}
           ${error_field("NO_TEXT", thing.name, "span")}
           ${error_field("TOO_OLD", "parent", "span")}
+          ${error_field("THREAD_LOCKED", "parent", "span")}
           ${error_field("DELETED_COMMENT", "parent", "span")}
           ${error_field("DELETED_LINK", "parent", "span")}
           ${error_field("USER_BLOCKED", "parent", "span")}