diff --git a/phpcs-rulesets/plugin-review.xml b/phpcs-rulesets/plugin-review.xml
index b4d5eedec..8d1e16c4d 100644
--- a/phpcs-rulesets/plugin-review.xml
+++ b/phpcs-rulesets/plugin-review.xml
@@ -56,6 +56,11 @@
 		<severity>7</severity>
 	</rule>
 
+	<!-- Prohibit the use of HEREDOC or NOWDOC. -->
+	<rule ref="Squiz.PHP.Heredoc">
+		<severity>7</severity>
+	</rule>
+
 	<!-- Prohibit the use of the `goto` PHP language construct. -->
 	<rule ref="Generic.PHP.DiscourageGoto.Found">
 		<type>error</type>
diff --git a/tests/phpunit/testdata/plugins/test-plugin-review-phpcs-errors/load.php b/tests/phpunit/testdata/plugins/test-plugin-review-phpcs-errors/load.php
index 96e8669a5..ac4caf474 100644
--- a/tests/phpunit/testdata/plugins/test-plugin-review-phpcs-errors/load.php
+++ b/tests/phpunit/testdata/plugins/test-plugin-review-phpcs-errors/load.php
@@ -24,3 +24,9 @@
 
 query_posts( 'cat=3' );
 wp_reset_query();
+
+$str = <<<EOD
+Example of string
+spanning multiple lines
+using heredoc syntax.
+EOD;
diff --git a/tests/phpunit/tests/Checker/Checks/Plugin_Review_PHPCS_Check_Tests.php b/tests/phpunit/tests/Checker/Checks/Plugin_Review_PHPCS_Check_Tests.php
index 29171a712..cf95371a8 100644
--- a/tests/phpunit/tests/Checker/Checks/Plugin_Review_PHPCS_Check_Tests.php
+++ b/tests/phpunit/tests/Checker/Checks/Plugin_Review_PHPCS_Check_Tests.php
@@ -32,6 +32,9 @@ public function test_run_with_errors() {
 		$this->assertArrayHasKey( 'code', $errors['load.php'][6][1][0] );
 		$this->assertEquals( 'Generic.PHP.DisallowShortOpenTag.Found', $errors['load.php'][6][1][0]['code'] );
 
+		// Check for Squiz.PHP.Heredoc.NotAllowed error on Line no 28 and column no at 8.
+		$this->assertEquals( 'Squiz.PHP.Heredoc.NotAllowed', $errors['load.php'][28][8][0]['code'] );
+
 		// Check for WordPress.WP.DeprecatedFunctions.the_author_emailFound error on Line no 12 and column no at 5.
 		$this->assertArrayHasKey( 12, $errors['load.php'] );
 		$this->assertArrayHasKey( 5, $errors['load.php'][12] );