diff --git a/src/wp-includes/comment.php b/src/wp-includes/comment.php
index 49c9c6b2cb966..a2d7409d0c0de 100644
--- a/src/wp-includes/comment.php
+++ b/src/wp-includes/comment.php
@@ -1574,13 +1574,38 @@ function wp_delete_comment( $comment_id, $force_delete = false ) {
  * If Trash is disabled, comment is permanently deleted.
  *
  * @since 2.9.0
+ * @since 6.9.0 Any child notes are deleted when deleting a note.
  *
  * @param int|WP_Comment $comment_id Comment ID or WP_Comment object.
  * @return bool True on success, false on failure.
  */
 function wp_trash_comment( $comment_id ) {
 	if ( ! EMPTY_TRASH_DAYS ) {
-		return wp_delete_comment( $comment_id, true );
+		$comment = get_comment( $comment_id );
+		$success = wp_delete_comment( $comment_id, true );
+
+		if ( ! $success ) {
+			return false;
+		}
+
+		// Also delete children of top level 'note' type comments.
+		if ( $comment && 'note' === $comment->comment_type && 0 === (int) $comment->comment_parent ) {
+			$children = $comment->get_children(
+				array(
+					'fields' => 'ids',
+					'status' => 'all',
+					'type'   => 'note',
+				)
+			);
+
+			foreach ( $children as $child_id ) {
+				if ( ! wp_delete_comment( $child_id, true ) ) {
+					$success = false;
+				}
+			}
+		}
+
+		return $success;
 	}
 
 	$comment = get_comment( $comment_id );
@@ -1616,6 +1641,25 @@ function wp_trash_comment( $comment_id ) {
 		 */
 		do_action( 'trashed_comment', $comment->comment_ID, $comment );
 
+		// For top level 'note' type comments, also trash children.
+		if ( 'note' === $comment->comment_type && 0 === (int) $comment->comment_parent ) {
+			$children = $comment->get_children(
+				array(
+					'fields' => 'ids',
+					'status' => 'all',
+					'type'   => 'note',
+				)
+			);
+
+			$success = true;
+			foreach ( $children as $child_id ) {
+				if ( ! wp_trash_comment( $child_id ) ) {
+					$success = false;
+				}
+			}
+			return $success;
+		}
+
 		return true;
 	}
 
diff --git a/tests/phpunit/tests/comment.php b/tests/phpunit/tests/comment.php
index a8f15e1deaec3..5c5ff192bf831 100644
--- a/tests/phpunit/tests/comment.php
+++ b/tests/phpunit/tests/comment.php
@@ -1672,4 +1672,224 @@ public function test_unspam_should_invalidate_comment_cache() {
 
 		$this->assertSame( '1', $comment->comment_approved );
 	}
+
+	/**
+	 * Tests that trashing a top-level note also trashes all direct child notes.
+	 *
+	 * @covers ::wp_trash_comment
+	 * @dataProvider data_comment_approved_statuses
+	 */
+	public function test_wp_trash_comment_trashes_child_notes( $approved_status ) {
+		// Create a parent note (top-level, comment_parent=0).
+		$parent_note = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => 0,
+				'comment_approved' => $approved_status,
+			)
+		);
+
+		// Create child notes under the parent.
+		$child_note_1 = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => $parent_note,
+				'comment_approved' => $approved_status,
+			)
+		);
+
+		$child_note_2 = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => $parent_note,
+				'comment_approved' => $approved_status,
+			)
+		);
+
+		$child_note_3 = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => $parent_note,
+				'comment_approved' => $approved_status,
+			)
+		);
+
+		// Trash the parent note.
+		wp_trash_comment( $parent_note );
+
+		// Verify parent note is trashed.
+		$this->assertSame( 'trash', get_comment( $parent_note )->comment_approved );
+
+		// Verify all child notes are also trashed.
+		$this->assertSame( 'trash', get_comment( $child_note_1 )->comment_approved );
+		$this->assertSame( 'trash', get_comment( $child_note_2 )->comment_approved );
+		$this->assertSame( 'trash', get_comment( $child_note_3 )->comment_approved );
+	}
+
+	/**
+	 * Data provider for test_wp_trash_comment_trashes_child_notes.
+	 */
+	public function data_comment_approved_statuses() {
+		return array(
+			array( '1' ),
+			array( '0' ),
+		);
+	}
+
+	/**
+	 * Tests that trashing a regular comment does NOT trash its children.
+	 *
+	 * @covers ::wp_trash_comment
+	 */
+	public function test_wp_trash_comment_does_not_trash_child_comments() {
+		// Create a parent comment (default type='comment').
+		$parent_comment = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'comment',
+				'comment_parent'   => 0,
+				'comment_approved' => '1',
+			)
+		);
+
+		// Create child comments under the parent.
+		$child_comment_1 = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'comment',
+				'comment_parent'   => $parent_comment,
+				'comment_approved' => '1',
+			)
+		);
+
+		$child_comment_2 = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'comment',
+				'comment_parent'   => $parent_comment,
+				'comment_approved' => '1',
+			)
+		);
+
+		// Trash the parent comment.
+		wp_trash_comment( $parent_comment );
+
+		// Verify parent comment is trashed.
+		$this->assertSame( 'trash', get_comment( $parent_comment )->comment_approved );
+
+		// Verify child comments are NOT trashed (maintaining existing behavior).
+		$this->assertSame( '1', get_comment( $child_comment_1 )->comment_approved );
+		$this->assertSame( '1', get_comment( $child_comment_2 )->comment_approved );
+	}
+
+	/**
+	 * Tests that trashing a child note does not affect parent or siblings.
+	 *
+	 * @covers ::wp_trash_comment
+	 */
+	public function test_wp_trash_comment_child_note_does_not_affect_parent_or_siblings() {
+		// Create a parent note.
+		$parent_note = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => 0,
+				'comment_approved' => '1',
+			)
+		);
+
+		// Create multiple child notes.
+		$child_note_1 = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => $parent_note,
+				'comment_approved' => '1',
+			)
+		);
+
+		$child_note_2 = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => $parent_note,
+				'comment_approved' => '1',
+			)
+		);
+
+		$child_note_3 = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => $parent_note,
+				'comment_approved' => '1',
+			)
+		);
+
+		// Trash only one child note.
+		wp_trash_comment( $child_note_2 );
+
+		// Verify the parent note is still approved.
+		$this->assertSame( '1', get_comment( $parent_note )->comment_approved );
+
+		// Verify the trashed child is trashed.
+		$this->assertSame( 'trash', get_comment( $child_note_2 )->comment_approved );
+
+		// Verify sibling notes are still approved.
+		$this->assertSame( '1', get_comment( $child_note_1 )->comment_approved );
+		$this->assertSame( '1', get_comment( $child_note_3 )->comment_approved );
+	}
+
+	/**
+	 * Tests that only top-level notes trigger child deletion.
+	 *
+	 * @covers ::wp_trash_comment
+	 */
+	public function test_wp_trash_comment_only_top_level_notes_trigger_child_deletion() {
+		// Create a parent note.
+		$parent_note = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => 0,
+				'comment_approved' => '1',
+			)
+		);
+
+		// Create a child note (not top-level, has comment_parent > 0).
+		$child_note = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => $parent_note,
+				'comment_approved' => '1',
+			)
+		);
+
+		// Create a sibling note (also not top-level).
+		$sibling_note = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_type'     => 'note',
+				'comment_parent'   => $parent_note,
+				'comment_approved' => '1',
+			)
+		);
+
+		// Trash the child note (which has comment_parent > 0).
+		wp_trash_comment( $child_note );
+
+		// Verify the child note is trashed.
+		$this->assertSame( 'trash', get_comment( $child_note )->comment_approved );
+
+		// Verify the parent note is NOT trashed.
+		$this->assertSame( '1', get_comment( $parent_note )->comment_approved );
+
+		// Verify the sibling note is NOT trashed (no cascade since child is not top-level).
+		$this->assertSame( '1', get_comment( $sibling_note )->comment_approved );
+	}
 }