diff --git src/wp-includes/update.php src/wp-includes/update.php
index e23811b..f065d09 100644
--- src/wp-includes/update.php
+++ src/wp-includes/update.php
@@ -736,6 +736,23 @@ function wp_clean_update_cache() {
 	delete_site_transient( 'update_core' );
 }
 
+/**
+ * Reset PHP opcache
+ *
+ * @since 4.9.5
+ */
+function wp_opcache_reset() {
+	if ( ! function_exists( 'opcache_reset' ) ) {
+		return;
+	}
+
+	if ( ! empty( ini_get( 'opcache.restrict_api' ) ) && strpos( __FILE__, ini_get( 'opcache.restrict_api' ) ) !== 0 ) {
+		return;
+	}
+
+	opcache_reset();
+}
+
 if ( ( ! is_main_site() && ! is_network_admin() ) || wp_doing_ajax() ) {
 	return;
 }
@@ -760,3 +777,5 @@ add_action( 'update_option_WPLANG', 'wp_clean_update_cache' , 10, 0 );
 add_action( 'wp_maybe_auto_update', 'wp_maybe_auto_update' );
 
 add_action( 'init', 'wp_schedule_update_checks' );
+
+add_action( 'upgrader_process_complete', 'wp_opcache_reset' );