diff --git a/extensions/flags/js/src/admin/components/FlagsSettingsModal.js b/extensions/flags/js/src/admin/components/FlagsSettingsModal.js
index 16e457dc4..3eba22408 100644
--- a/extensions/flags/js/src/admin/components/FlagsSettingsModal.js
+++ b/extensions/flags/js/src/admin/components/FlagsSettingsModal.js
@@ -14,6 +14,12 @@ export default class FlagsSettingsModal extends SettingsModal {
       <div className="Form-group">
         <label>{app.translator.trans('flarum-flags.admin.settings.guidelines_url_label')}</label>
         <input className="FormControl" bidi={this.setting('flarum-flags.guidelines_url')}/>
+      </div>,
+      <div className="Form-group">
+        <label className="checkbox">
+          <input type="checkbox" bidi={this.setting('flarum-flags.can_flag_own')}/>
+          {app.translator.trans('flarum-flags.admin.settings.user_can_flag_own_posts')}
+        </label>
       </div>
     ];
   }
diff --git a/extensions/flags/js/src/forum/addFlagControl.js b/extensions/flags/js/src/forum/addFlagControl.js
index 7a2bfba9d..43cc59e33 100644
--- a/extensions/flags/js/src/forum/addFlagControl.js
+++ b/extensions/flags/js/src/forum/addFlagControl.js
@@ -7,7 +7,7 @@ import FlagPostModal from './components/FlagPostModal';
 
 export default function() {
   extend(PostControls, 'userControls', function(items, post) {
-    if (post.isHidden() || post.contentType() !== 'comment' || !post.canFlag() || post.user() === app.session.user) return;
+    if (post.isHidden() || post.contentType() !== 'comment' || !post.canFlag()) return;
 
     items.add('flag',
       <Button icon="fas fa-flag" onclick={() => app.modal.show(new FlagPostModal({post}))}>{app.translator.trans('flarum-flags.forum.post_controls.flag_button')}</Button>
diff --git a/extensions/flags/js/src/forum/addFlagsToPosts.js b/extensions/flags/js/src/forum/addFlagsToPosts.js
index 003e9fc23..7e4039323 100644
--- a/extensions/flags/js/src/forum/addFlagsToPosts.js
+++ b/extensions/flags/js/src/forum/addFlagsToPosts.js
@@ -4,6 +4,7 @@ import Post from 'flarum/components/Post';
 import Button from 'flarum/components/Button';
 import ItemList from 'flarum/utils/ItemList';
 import PostControls from 'flarum/utils/PostControls';
+import humanTime from 'flarum/utils/humanTime';
 
 export default function() {
   extend(Post.prototype, 'attrs', function(attrs) {
@@ -105,9 +106,10 @@ export default function() {
       const user = flag.user();
       const reason = flag.reason();
       const detail = flag.reasonDetail();
+      const time = humanTime(flag.createdAt());
 
       return [
-        app.translator.trans(reason ? 'flarum-flags.forum.post.flagged_by_with_reason_text' : 'flarum-flags.forum.post.flagged_by_text', {user, reason}),
+        app.translator.trans(reason ? 'flarum-flags.forum.post.flagged_by_with_reason_text' : 'flarum-flags.forum.post.flagged_by_text', {time, user, reason}),
         detail ? <span className="Post-flagged-detail">{detail}</span> : ''
       ];
     }
diff --git a/extensions/flags/js/src/forum/components/FlagPostModal.js b/extensions/flags/js/src/forum/components/FlagPostModal.js
index 9921a54a2..d0cc1c8b6 100644
--- a/extensions/flags/js/src/forum/components/FlagPostModal.js
+++ b/extensions/flags/js/src/forum/components/FlagPostModal.js
@@ -12,7 +12,7 @@ export default class FlagPostModal extends Modal {
   }
 
   className() {
-    return 'FlagPostModal Modal--small';
+    return 'FlagPostModal Modal--medium';
   }
 
   title() {
@@ -46,6 +46,9 @@ export default class FlagPostModal extends Modal {
                 <input type="radio" name="reason" checked={this.reason() === 'off_topic'} value="off_topic" onclick={m.withAttr('value', this.reason)}/>
                 <strong>{app.translator.trans('flarum-flags.forum.flag_post.reason_off_topic_label')}</strong>
                 {app.translator.trans('flarum-flags.forum.flag_post.reason_off_topic_text')}
+                {this.reason() === 'off_topic' ? (
+                  <textarea className="FormControl" placeholder={app.translator.trans('flarum-flags.forum.flag_post.optional_details')} value={this.reasonDetail()} oninput={m.withAttr('value', this.reasonDetail)}></textarea>
+                ) : ''}
               </label>
 
               <label className="checkbox">
@@ -54,12 +57,18 @@ export default class FlagPostModal extends Modal {
                 {app.translator.trans('flarum-flags.forum.flag_post.reason_inappropriate_text', {
                   a: guidelinesUrl ? <a href={guidelinesUrl} target="_blank"/> : undefined
                 })}
+                {this.reason() === 'inappropriate' ? (
+                  <textarea className="FormControl" placeholder={app.translator.trans('flarum-flags.forum.flag_post.optional_details')} value={this.reasonDetail()} oninput={m.withAttr('value', this.reasonDetail)}></textarea>
+                ) : ''}
               </label>
 
               <label className="checkbox">
                 <input type="radio" name="reason" checked={this.reason() === 'spam'} value="spam" onclick={m.withAttr('value', this.reason)}/>
                 <strong>{app.translator.trans('flarum-flags.forum.flag_post.reason_spam_label')}</strong>
                 {app.translator.trans('flarum-flags.forum.flag_post.reason_spam_text')}
+                {this.reason() === 'spam' ? (
+                  <textarea className="FormControl" placeholder={app.translator.trans('flarum-flags.forum.flag_post.optional_details')} value={this.reasonDetail()} oninput={m.withAttr('value', this.reasonDetail)}></textarea>
+                ) : ''}
               </label>
 
               <label className="checkbox">
@@ -98,9 +107,17 @@ export default class FlagPostModal extends Modal {
         user: app.session.user,
         post: this.props.post
       }
-    })
+    }, {errorHandler: this.onerror.bind(this)})
       .then(() => this.success = true)
       .catch(() => {})
       .then(this.loaded.bind(this));
   }
+
+  onerror(error) {
+    if (error.status === 422) {
+      error.alert.props.children = app.translator.trans('flarum-flags.forum.flag_post.reason-needed');
+    }
+
+    super.onerror(error);
+  }
 }
diff --git a/extensions/flags/migrations/2019_10_22_000000_change_reason_text_col_type.php b/extensions/flags/migrations/2019_10_22_000000_change_reason_text_col_type.php
new file mode 100644
index 000000000..6059b8f28
--- /dev/null
+++ b/extensions/flags/migrations/2019_10_22_000000_change_reason_text_col_type.php
@@ -0,0 +1,25 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Schema\Builder;
+
+return [
+    'up' => function (Builder $schema) {
+        $schema->table('flags', function (Blueprint $table) {
+            $table->text('reason_detail')->change();
+        });
+    },
+
+    'down' => function (Builder $schema) {
+        $schema->table('flags', function (Blueprint $table) {
+            $table->string(['reason_detail'])->change();
+        });
+    }
+];
diff --git a/extensions/flags/src/Command/CreateFlagHandler.php b/extensions/flags/src/Command/CreateFlagHandler.php
index d180d5bd3..29137d846 100644
--- a/extensions/flags/src/Command/CreateFlagHandler.php
+++ b/extensions/flags/src/Command/CreateFlagHandler.php
@@ -10,9 +10,13 @@
 namespace Flarum\Flags\Command;
 
 use Flarum\Flags\Flag;
+use Flarum\Foundation\ValidationException;
 use Flarum\Post\CommentPost;
 use Flarum\Post\PostRepository;
+use Flarum\Settings\SettingsRepositoryInterface;
 use Flarum\User\AssertPermissionTrait;
+use Flarum\User\Exception\PermissionDeniedException;
+use Symfony\Component\Translation\TranslatorInterface;
 use Tobscure\JsonApi\Exception\InvalidParameterException;
 
 class CreateFlagHandler
@@ -25,17 +29,31 @@ class CreateFlagHandler
     protected $posts;
 
     /**
-     * @param PostRepository $posts
+     * @var TranslatorInterface
      */
-    public function __construct(PostRepository $posts)
+    protected $translator;
+
+    /**
+     * @var SettingsRepositoryInterface
+     */
+    protected $settings;
+
+    /**
+     * @param PostRepository $posts
+     * @param TranslatorInterface $translator
+     */
+    public function __construct(PostRepository $posts, TranslatorInterface $translator, SettingsRepositoryInterface $settings)
     {
         $this->posts = $posts;
+        $this->translator = $translator;
+        $this->settings = $settings;
     }
 
     /**
      * @param CreateFlag $command
      * @return Flag
      * @throws InvalidParameterException
+     * @throws ValidationException
      */
     public function handle(CreateFlag $command)
     {
@@ -51,6 +69,16 @@ class CreateFlagHandler
 
         $this->assertCan($actor, 'flag', $post);
 
+        if ($actor->id === $post->user_id && ! $this->settings->get('flarum-flags.can_flag_own')) {
+            throw new PermissionDeniedException();
+        }
+
+        if (array_get($data, 'attributes.reason') === null && array_get($data, 'attributes.reasonDetail') === '') {
+            throw new ValidationException([
+                'message' => $this->translator->trans('flarum-flags.forum.flag_post.reason-needed')
+            ]);
+        }
+
         Flag::unguard();
 
         $flag = Flag::firstOrNew([
diff --git a/extensions/flags/src/Listener/AddFlagsApiAttributes.php b/extensions/flags/src/Listener/AddFlagsApiAttributes.php
index 3138cb242..b48032d98 100755
--- a/extensions/flags/src/Listener/AddFlagsApiAttributes.php
+++ b/extensions/flags/src/Listener/AddFlagsApiAttributes.php
@@ -14,6 +14,7 @@ use Flarum\Api\Serializer\CurrentUserSerializer;
 use Flarum\Api\Serializer\ForumSerializer;
 use Flarum\Api\Serializer\PostSerializer;
 use Flarum\Flags\Flag;
+use Flarum\Post\CommentPost;
 use Flarum\Settings\SettingsRepositoryInterface;
 use Flarum\User\User;
 
@@ -49,7 +50,7 @@ class AddFlagsApiAttributes
         }
 
         if ($event->isSerializer(PostSerializer::class)) {
-            $event->attributes['canFlag'] = $event->actor->can('flag', $event->model);
+            $event->attributes['canFlag'] = $event->actor->can('flag', $event->model) && $this->checkFlagOwnPostSetting($event->actor, $event->model);
         }
     }
 
@@ -76,4 +77,19 @@ class AddFlagsApiAttributes
 
         return $query->distinct()->count('flags.post_id');
     }
+
+    /**
+     * @param User $actor
+     * @param CommentPost $post
+     * @return bool
+     */
+    protected function checkFlagOwnPostSetting(User $actor, CommentPost $post): bool
+    {
+        if ($actor->id === $post->user_id) {
+            // If $actor is the post author, check to see if the setting is enabled
+            return (bool) $this->settings->get('flarum-flags.can_flag_own');
+        }
+        // $actor is not the post author
+        return true;
+    }
 }