diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index ca5b8af285..878ed7c902 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -4052,25 +4052,6 @@ function validate_file( $file, $allowed_files = '' ) {
 	return 0;
 }
 
-/**
- * Determine if SSL is used.
- *
- * @since 2.6.0
- *
- * @return bool True if SSL, false if not used.
- */
-function is_ssl() {
-	if ( isset($_SERVER['HTTPS']) ) {
-		if ( 'on' == strtolower($_SERVER['HTTPS']) )
-			return true;
-		if ( '1' == $_SERVER['HTTPS'] )
-			return true;
-	} elseif ( isset($_SERVER['SERVER_PORT']) && ( '443' == $_SERVER['SERVER_PORT'] ) ) {
-		return true;
-	}
-	return false;
-}
-
 /**
  * Whether to force SSL used for the Administration Screens.
  *
diff --git a/src/wp-includes/load.php b/src/wp-includes/load.php
index f474c5c87e..54ed0400be 100644
--- a/src/wp-includes/load.php
+++ b/src/wp-includes/load.php
@@ -949,3 +949,26 @@ function wp_installing( $is_installing = null ) {
 
 	return (bool) $installing;
 }
+
+/**
+ * Determines if SSL is used.
+ *
+ * @since 2.6.0
+ * @since 4.6.0 Moved from functions.php to load.php
+ *
+ * @return bool True if SSL, otherwise false.
+ */
+function is_ssl() {
+	if ( isset( $_SERVER['HTTPS'] ) ) {
+		if ( 'on' == strtolower( $_SERVER['HTTPS'] ) ) {
+			return true;
+		}
+
+		if ( '1' == $_SERVER['HTTPS'] ) {
+			return true;
+		}
+	} elseif ( isset($_SERVER['SERVER_PORT'] ) && ( '443' == $_SERVER['SERVER_PORT'] ) ) {
+		return true;
+	}
+	return false;
+}