diff --git a/js/qsm-admin.js b/js/qsm-admin.js
index 437eff05..f5ca5e80 100644
--- a/js/qsm-admin.js
+++ b/js/qsm-admin.js
@@ -4394,11 +4394,24 @@ var QSM_Quiz_Broadcast_Channel;
 
 }(jQuery));
 
-
+function qsm_check_email_sent_option() {
+    if (jQuery('input[name="send_email"]').prop('checked') === true) {
+        jQuery('#check_already_sent_email input[name="check_already_sent_email"]').prop( 'disabled', false );
+        jQuery('#check_already_sent_email').show();
+    } else {
+        jQuery('#check_already_sent_email input[name="check_already_sent_email"]').prop( 'disabled', true );
+        jQuery('#check_already_sent_email').hide();
+    }
+}
 /**
  * QSM - failed submission data table action
  */
 (function ($) {
+    qsm_check_email_sent_option();
+    $(document).on('change', 'input[name="send_email"]', function (event) {
+        event.preventDefault();
+        qsm_check_email_sent_option();
+    });
     function submit_failed_submission_action_notice( res ) {
         if ( 'object' !== typeof res || null === res || undefined === res.message  ) {
             return false;
diff --git a/php/classes/class-qsm-emails.php b/php/classes/class-qsm-emails.php
index c10da820..850781c6 100644
--- a/php/classes/class-qsm-emails.php
+++ b/php/classes/class-qsm-emails.php
@@ -173,7 +173,7 @@ public static function send_emails( $transient_id ) {
 		if ( 0 == $email_send && ! empty( $default_email_content ) ) {
 			self::send_results_email( $response_data, $default_email_to, $default_email_subject, $default_email_content, $default_email_reply_to, $default_index );
 		}
-
+		delete_transient( 'qsm_already_sent_emails_' . $response_data['quiz_id'] );
 		remove_filter( 'wp_mail_content_type', 'mlw_qmn_set_html_content_type' );
 	}
 
@@ -266,13 +266,25 @@ public static function send_results_email( $response_data, $to, $subject, $conte
 			$attachments = apply_filters( 'qsm_admin_email_attachments', $attachments, $response_data );
 		}
 
+		$quiz_options = maybe_unserialize( $response_data['quiz_settings']['quiz_options'] );
+		// Check if email has already been sent to the user for this quiz
+		if ( isset( $quiz_options['check_already_sent_email'] ) && 1 == $quiz_options['check_already_sent_email'] ) {
+			$already_sent_emails = get_transient( 'qsm_already_sent_emails_' . $response_data['quiz_id'] );
+		}
+		$already_sent_emails = ! empty( $already_sent_emails ) ? $already_sent_emails : array();
+
 		// Cycle through each to email address and send the email.
 		foreach ( $to_array as $to_email ) {
-			if ( is_email( $to_email ) ) {
+			if ( is_email( $to_email ) && ! in_array( $to_email, $already_sent_emails ) ) {
 				$mailResult = wp_mail( $to_email, $subject, $content, $headers, $attachments );
 				if ( $mailResult ) {
 					do_action( 'qsm_after_sending_email', $response_data, $to_email, $subject );
-				}else {
+					// Add the email to the list of already sent emails for this quiz
+					if ( isset( $quiz_options['check_already_sent_email'] ) && 1 == $quiz_options['check_already_sent_email'] ) {
+						$already_sent_emails[] = $to_email;
+						set_transient( 'qsm_already_sent_emails_' . $response_data['quiz_id'], $already_sent_emails, 3600 );
+					}
+				} else {
 					$mlwQuizMasterNext->log_manager->add( 'There has been an error in wp_mail. Please check SMTP details mail not sending. Error Code: 0001', 0, 'error' );
 				}
 			}
diff --git a/php/classes/class-qsm-install.php b/php/classes/class-qsm-install.php
index 869207ef..42ef70f3 100644
--- a/php/classes/class-qsm-install.php
+++ b/php/classes/class-qsm-install.php
@@ -450,6 +450,16 @@ public function register_default_settings() {
 					),
 					'default' => 1,
 				),
+				'check_already_sent_email'      => array(
+					'type'    => 'checkbox',
+					'options' => array(
+						array(
+							'label' => __( 'Not send email if already sent', 'quiz-master-next' ),
+							'value' => 1,
+						),
+					),
+					'default' => 0,
+				),
 			),
 			'help'       => '',
 			'option_tab' => 'quiz_submission',