diff --git a/src/wp-admin/includes/schema.php b/src/wp-admin/includes/schema.php
index d48846f739..a59c7c36ce 100644
--- a/src/wp-admin/includes/schema.php
+++ b/src/wp-admin/includes/schema.php
@@ -535,6 +535,13 @@ function populate_options( array $options = array() ) {
 		'disallowed_keys'                 => '',
 		'comment_previously_approved'     => 1,
 		'auto_plugin_theme_update_emails' => array(),
+
+		// 5.6.0
+		'auto_update_core_dev'            => 'enabled',
+		'auto_update_core_minor'          => 'enabled',
+		// Default to enabled for new installs.
+		// See https://core.trac.wordpress.org/ticket/51742.
+		'auto_update_core_major'          => 'enabled',
 	);
 
 	// 3.3.0
diff --git a/src/wp-admin/includes/upgrade.php b/src/wp-admin/includes/upgrade.php
index 3342c76b65..ca95940b49 100644
--- a/src/wp-admin/includes/upgrade.php
+++ b/src/wp-admin/includes/upgrade.php
@@ -2255,6 +2255,11 @@ function upgrade_560() {
 	if ( ! is_null( $post_category_exists ) ) {
 		$wpdb->query( "ALTER TABLE $wpdb->posts DROP COLUMN `post_category`" );
 	}
+
+	// When upgrading from WP < 5.6.0 set the core major auto-updates option to `unset` by default.
+	// This overrides the same option from populate_options() that is intended for new installs.
+	// See https://core.trac.wordpress.org/ticket/51742.
+	update_option( 'auto_update_core_major', 'unset' );
 }
 
 /**