diff --git a/features/sidebar.feature b/features/sidebar.feature
index 5e5d4315..cf56f6a1 100644
--- a/features/sidebar.feature
+++ b/features/sidebar.feature
@@ -23,6 +23,27 @@ Feature: Manage WordPress sidebars
       4
       """
 
+  Scenario: List inactive sidebars
+    When I run `wp sidebar list --inactive --format=count`
+    Then STDOUT should be:
+      """
+      0
+      """
+
+    When I run `wp eval 'update_option( "sidebars_widgets", array_merge( wp_get_sidebars_widgets(), [ "orphaned-sidebar-1" => [] ] ) );'`
+    And I run `wp sidebar list --inactive --fields=id --format=csv`
+    Then STDOUT should be:
+      """
+      id
+      orphaned-sidebar-1
+      """
+
+    When I run `wp sidebar list --fields=id --format=ids`
+    Then STDOUT should not contain:
+      """
+      orphaned-sidebar-1
+      """
+
   Scenario: Get sidebar details
     When I run `wp sidebar get sidebar-1`
     Then STDOUT should contain:
diff --git a/features/widget-reset.feature b/features/widget-reset.feature
index 917caef8..6f923dc1 100644
--- a/features/widget-reset.feature
+++ b/features/widget-reset.feature
@@ -24,7 +24,7 @@ Feature: Reset WordPress sidebars
     When I try `wp widget reset`
     Then STDERR should be:
       """
-      Error: Please specify one or more sidebars, or use --all.
+      Error: Please specify one or more sidebars, or use --all or --inactive.
       """
 
     When I try `wp widget reset sidebar-1`
@@ -153,3 +153,37 @@ Feature: Reset WordPress sidebars
       """
       calendar-1 search-1
       """
+
+  Scenario: Reset inactive sidebars
+    When I try `wp widget reset --inactive`
+    Then STDERR should be:
+      """
+      Error: No inactive sidebars found.
+      """
+    And the return code should be 1
+
+    When I run `wp widget add calendar sidebar-1 --title="Calendar"`
+    Then STDOUT should not be empty
+
+    # Simulate an inactive (unregistered) sidebar by moving widget data to an orphaned key
+    When I run `wp eval '$w = wp_get_sidebars_widgets(); $w["orphaned-sidebar-1"] = $w["sidebar-1"]; $w["sidebar-1"] = []; update_option( "sidebars_widgets", $w );'`
+
+    And I run `wp sidebar list --inactive --fields=id --format=ids`
+    Then STDOUT should be:
+      """
+      orphaned-sidebar-1
+      """
+
+    When I run `wp widget reset --inactive`
+    Then STDOUT should be:
+      """
+      Sidebar 'orphaned-sidebar-1' reset.
+      Success: Reset 1 of 1 sidebars.
+      """
+    And the return code should be 0
+
+    When I run `wp widget list wp_inactive_widgets --format=ids`
+    Then STDOUT should contain:
+      """
+      calendar-1
+      """
diff --git a/src/Sidebar_Command.php b/src/Sidebar_Command.php
index 03a15b73..aa8439d4 100644
--- a/src/Sidebar_Command.php
+++ b/src/Sidebar_Command.php
@@ -29,6 +29,9 @@ class Sidebar_Command extends WP_CLI_Command {
 	 *
 	 * ## OPTIONS
 	 *
+	 * [--inactive]
+	 * : If set, only inactive sidebars will be listed.
+	 *
 	 * [--fields=<fields>]
 	 * : Limit the output to specific object fields.
 	 *
@@ -68,6 +71,10 @@ class Sidebar_Command extends WP_CLI_Command {
 	 *     "Widget Area",sidebar-1
 	 *     "Inactive Widgets",wp_inactive_widgets
 	 *
+	 *     $ wp sidebar list --inactive --fields=id --format=csv
+	 *     id
+	 *     old-sidebar-1
+	 *
 	 * @subcommand list
 	 */
 	public function list_( $args, $assoc_args ) {
@@ -75,16 +82,62 @@ public function list_( $args, $assoc_args ) {
 
 		Utils\wp_register_unused_sidebar();
 
-		if ( ! empty( $assoc_args['format'] ) && 'ids' === $assoc_args['format'] ) {
-			$sidebars = wp_list_pluck( $wp_registered_sidebars, 'id' );
+		$inactive = Utils\get_flag_value( $assoc_args, 'inactive', false );
+
+		if ( $inactive ) {
+			$sidebars = [];
+			foreach ( self::get_inactive_sidebar_ids() as $sidebar_id ) {
+				$sidebars[ $sidebar_id ] = [
+					'name'          => $sidebar_id,
+					'id'            => $sidebar_id,
+					'description'   => '',
+					'class'         => '',
+					'before_widget' => '',
+					'after_widget'  => '',
+					'before_title'  => '',
+					'after_title'   => '',
+				];
+			}
 		} else {
 			$sidebars = $wp_registered_sidebars;
 		}
 
+		if ( ! empty( $assoc_args['format'] ) && 'ids' === $assoc_args['format'] ) {
+			$sidebars = wp_list_pluck( $sidebars, 'id' );
+		}
+
 		$formatter = new Formatter( $assoc_args, $this->fields );
 		$formatter->display_items( $sidebars );
 	}
 
+	/**
+	 * Returns the IDs of sidebars that exist in the database but are not currently registered.
+	 *
+	 * @return string[]
+	 */
+	public static function get_inactive_sidebar_ids() {
+		global $wp_registered_sidebars;
+
+		$sidebars_widgets = get_option( 'sidebars_widgets', [] );
+		if ( ! is_array( $sidebars_widgets ) ) {
+			$sidebars_widgets = [];
+		}
+		if ( isset( $sidebars_widgets['array_version'] ) ) {
+			unset( $sidebars_widgets['array_version'] );
+		}
+
+		$registered_ids = array_keys( $wp_registered_sidebars );
+
+		return array_values(
+			array_filter(
+				array_diff( array_keys( $sidebars_widgets ), $registered_ids ),
+				static function ( $id ) {
+					return 'wp_inactive_widgets' !== $id;
+				}
+			)
+		);
+	}
+
 	/**
 	 * Get details about a specific sidebar.
 	 *
diff --git a/src/Widget_Command.php b/src/Widget_Command.php
index 8b8619f7..4eed6ebd 100644
--- a/src/Widget_Command.php
+++ b/src/Widget_Command.php
@@ -478,53 +478,85 @@ public function delete( $args, $assoc_args ) {
 	 * [--all]
 	 * : If set, all sidebars will be reset.
 	 *
+	 * [--inactive]
+	 * : If set, all inactive sidebars will also be reset, in addition to any sidebars specified via <sidebar-id>... or selected with --all.
+	 *
 	 * ## EXAMPLES
 	 *
 	 *     # Reset a sidebar
 	 *     $ wp widget reset sidebar-1
-	 *     Success: Sidebar 'sidebar-1' reset.
+	 *     Sidebar 'sidebar-1' reset.
 	 *
 	 *     # Reset multiple sidebars
 	 *     $ wp widget reset sidebar-1 sidebar-2
-	 *     Success: Sidebar 'sidebar-1' reset.
-	 *     Success: Sidebar 'sidebar-2' reset.
+	 *     Sidebar 'sidebar-1' reset.
+	 *     Sidebar 'sidebar-2' reset.
 	 *
 	 *     # Reset all sidebars
 	 *     $ wp widget reset --all
-	 *     Success: Sidebar 'sidebar-1' reset.
-	 *     Success: Sidebar 'sidebar-2' reset.
-	 *     Success: Sidebar 'sidebar-3' reset.
+	 *     Sidebar 'sidebar-1' reset.
+	 *     Sidebar 'sidebar-2' reset.
+	 *     Sidebar 'sidebar-3' reset.
+	 *
+	 *     # Reset all inactive sidebars
+	 *     $ wp widget reset --inactive
+	 *     Sidebar 'old-sidebar-1' reset.
 	 */
 	public function reset( $args, $assoc_args ) {
 
 		global $wp_registered_sidebars;
 
-		$all = Utils\get_flag_value( $assoc_args, 'all', false );
+		$all      = Utils\get_flag_value( $assoc_args, 'all', false );
+		$inactive = Utils\get_flag_value( $assoc_args, 'inactive', false );
 
-		// Bail if no arguments and no all flag.
-		if ( ! $all && empty( $args ) ) {
-			WP_CLI::error( 'Please specify one or more sidebars, or use --all.' );
+		// Bail if no arguments and no --all or --inactive flag.
+		if ( ! $all && ! $inactive && empty( $args ) ) {
+			WP_CLI::error( 'Please specify one or more sidebars, or use --all or --inactive.' );
 		}
 
-		// Fetch all sidebars if all flag is set.
+		// Explicitly handle reserved sidebar ID for inactive widgets.
+		if ( in_array( 'wp_inactive_widgets', $args, true ) ) {
+			WP_CLI::error( "Sidebar 'wp_inactive_widgets' is reserved for inactive widgets and cannot be reset with this command. The --inactive flag only targets widgets from orphaned or unregistered sidebars, not 'wp_inactive_widgets' itself." );
+		}
+
+		// Fetch all registered sidebars if --all flag is set.
 		if ( $all ) {
 			$args = array_keys( $wp_registered_sidebars );
 		}
 
 		// Sidebar ID wp_inactive_widgets is reserved by WP core for inactive widgets.
-		if ( isset( $args['wp_inactive_widgets'] ) ) {
-			unset( $args['wp_inactive_widgets'] );
+		$args = array_values(
+			array_filter(
+				$args,
+				static function ( $id ) {
+					return 'wp_inactive_widgets' !== $id;
+				}
+			)
+		);
+
+		// Collect inactive (unregistered) sidebar IDs if --inactive flag is set.
+		$inactive_args = [];
+		if ( $inactive ) {
+			$inactive_args = Sidebar_Command::get_inactive_sidebar_ids();
 		}
 
-		// Check if no registered sidebar.
-		if ( empty( $args ) ) {
+		$all_args = array_merge( $args, $inactive_args );
+		$all_args = array_values( array_unique( $all_args ) );
+
+		// Check if there are no sidebars to reset.
+		if ( empty( $all_args ) ) {
+			if ( $inactive && empty( $inactive_args ) ) {
+				WP_CLI::error( 'No inactive sidebars found.' );
+			}
 			WP_CLI::error( 'No sidebar registered.' );
 		}
 
 		$count  = 0;
 		$errors = 0;
-		foreach ( $args as $sidebar_id ) {
-			if ( ! array_key_exists( $sidebar_id, $wp_registered_sidebars ) ) {
+		foreach ( $all_args as $sidebar_id ) {
+			// Skip registration validation for sidebars resolved via --inactive.
+			if ( ! in_array( $sidebar_id, $inactive_args, true ) &&
+				! array_key_exists( $sidebar_id, $wp_registered_sidebars ) ) {
 				WP_CLI::warning( sprintf( 'Invalid sidebar: %s', $sidebar_id ) );
 				++$errors;
 				continue;
@@ -550,7 +582,7 @@ public function reset( $args, $assoc_args ) {
 			}
 		}
 
-		Utils\report_batch_operation_results( 'sidebar', 'reset', count( $args ), $count, $errors );
+		Utils\report_batch_operation_results( 'sidebar', 'reset', count( $all_args ), $count, $errors );
 	}
 
 	/**