diff --git a/inc/config.php b/inc/config.php
index 2fecf59b..d589f203 100644
--- a/inc/config.php
+++ b/inc/config.php
@@ -679,6 +679,9 @@
 	// How many ban appeals can be made for a single ban?
 	$config['ban_appeals_max'] = 1;
 
+	// Maximum text length of an appeal.
+	$config['appeal_text_max_length'] = 300;
+
 	// Show moderator name on ban page.
 	$config['show_modname'] = false;
 
diff --git a/post.php b/post.php
index 3a313b81..ce269b03 100644
--- a/post.php
+++ b/post.php
@@ -1395,6 +1395,9 @@ if (isset($_POST['delete'])) {
 	if ($ban['expires'] && $ban['expires'] - $ban['created'] <= $config['ban_appeals_min_length']) {
 		error(_("You cannot appeal a ban of this length."));
 	}
+
+	if (strlen($_POST['appeal']) > $config['appeal_text_max_length'])
+		error(_("Your appeal is too long."));
 	
 	$query = query("SELECT `denied` FROM ``ban_appeals`` WHERE `ban_id` = $ban_id") or error(db_error());
 	$ban_appeals = $query->fetchAll(PDO::FETCH_COLUMN);
diff --git a/templates/banned.html b/templates/banned.html
index b4cdf3f9..3c759b35 100644
--- a/templates/banned.html
+++ b/templates/banned.html
@@ -135,7 +135,7 @@
 			{% endif %}
 			<form class="ban-appeal" action="" method="post">
 				<input type="hidden" name="ban_id" value="{{ ban.id }}">
-				<textarea name="appeal" rows="4" cols="40"></textarea>
+				<textarea name="appeal" rows="4" cols="40" maxlength="{{ config.appeal_text_max_length }}"></textarea>
 				<input type="submit" value="Submit">
 			</form>
 		{% endif %}