diff --git a/mod/forum/discuss.php b/mod/forum/discuss.php
index eb05d32907b..01c536548f0 100644
--- a/mod/forum/discuss.php
+++ b/mod/forum/discuss.php
@@ -230,7 +230,7 @@
     echo $OUTPUT->header();
 
     $headingvalue = format_string($forum->name);
-    if (has_capability('mod/forum:viewdiscussion', $modcontext)) {
+    if ((!isguestuser() && isloggedin()) && has_capability('mod/forum:viewdiscussion', $modcontext)) {
         // Discussion subscription.
         if (\mod_forum\subscriptions::is_subscribable($forum)) {
             $headingvalue .= ' ';
diff --git a/mod/forum/lib.php b/mod/forum/lib.php
index b3a63b1a099..6d114281ff8 100644
--- a/mod/forum/lib.php
+++ b/mod/forum/lib.php
@@ -3717,7 +3717,7 @@ function forum_print_discussion_header(&$post, $forum, $group=-1, $datestring=""
           userdate($usedate, $datestring).'</a>';
     echo "</td>\n";
 
-    if (has_capability('mod/forum:viewdiscussion', $modcontext)) {
+    if ((!isguestuser() && isloggedin()) && has_capability('mod/forum:viewdiscussion', $modcontext)) {
         // Discussion subscription.
         if (\mod_forum\subscriptions::is_subscribable($forum)) {
             echo '<td class="discussionsubscription">';
diff --git a/mod/forum/tests/behat/discussion_subscriptions.feature b/mod/forum/tests/behat/discussion_subscriptions.feature
index d05a83dd1bf..eccf524ac05 100644
--- a/mod/forum/tests/behat/discussion_subscriptions.feature
+++ b/mod/forum/tests/behat/discussion_subscriptions.feature
@@ -269,3 +269,38 @@ Feature: A user can control their own subscription preferences for a discussion
     And I follow "Test post subject two"
     And I follow "Reply"
     And the field "Discussion subscription" matches value "I don't want email copies of posts to this discussion"
+
+ Scenario: A guest should not be able to subscribe to a discussion
+   Given I click on "Home" "link" in the "Navigation" "block" 
+   And I add a "Forum" to section "1" and I fill the form with:
+     | Forum name        | Test forum name |
+     | Forum type        | Standard forum for general use |
+     | Description       | Test forum description |
+   And I add a new discussion to "Test forum name" forum with:
+     | Subject | Test post subject one |
+     | Message | Test post message one |
+   And I log out
+   When I log in as "guest"
+   And I follow "Test forum name"
+   Then "Not subscribed. Click to subscribe." "link" should not exist in the "Test post subject one" "table_row"
+   And "You are subscribed to this discussion. Click to unsubscribe." "link" should not exist in the "Test post subject one" "table_row"
+   And I follow "Test post subject one"
+   And "Not subscribed. Click to subscribe." "link" should not exist
+   And "You are subscribed to this discussion. Click to unsubscribe." "link" should not exist
+
+ Scenario: A user who is not logged in should not be able to subscribe to a discussion
+   Given I click on "Home" "link" in the "Navigation" "block" 
+   And I add a "Forum" to section "1" and I fill the form with:
+     | Forum name        | Test forum name |
+     | Forum type        | Standard forum for general use |
+     | Description       | Test forum description |
+   And I add a new discussion to "Test forum name" forum with:
+     | Subject | Test post subject one |
+     | Message | Test post message one |
+   And I log out
+   When I follow "Test forum name"
+   Then "Not subscribed. Click to subscribe." "link" should not exist in the "Test post subject one" "table_row"
+   And "You are subscribed to this discussion. Click to unsubscribe." "link" should not exist in the "Test post subject one" "table_row"
+   And I follow "Test post subject one"
+   And "Not subscribed. Click to subscribe." "link" should not exist
+   And "You are subscribed to this discussion. Click to unsubscribe." "link" should not exist