diff --git tests/phpunit/tests/term/query.php tests/phpunit/tests/term/query.php
index 09925cdc7b..55a39629e3 100644
--- tests/phpunit/tests/term/query.php
+++ tests/phpunit/tests/term/query.php
@@ -713,4 +713,62 @@ class Tests_Term_Query extends WP_UnitTestCase {
 
 		return $term;
 	}
+
+	/**
+	 * @ticket 44279
+	 */
+	public function test_childless_with_child_of() {
+		register_taxonomy(
+			'wptests_tax',
+			'post',
+			array(
+				'hierarchical' => true,
+			)
+		);
+
+		$t1 = self::factory()->term->create(
+			array(
+				'taxonomy' => 'wptests_tax',
+			)
+		);
+
+		$t2 = self::factory()->term->create(
+			array(
+				'taxonomy' => 'wptests_tax',
+				'parent'   => $t1,
+			)
+		);
+
+		$t3 = self::factory()->term->create(
+			array(
+				'taxonomy' => 'wptests_tax',
+				'parent'   => $t1,
+			)
+		);
+
+		$t4 = self::factory()->term->create(
+			array(
+				'taxonomy' => 'wptests_tax',
+			)
+		);
+
+		$t5 = self::factory()->term->create(
+			array(
+				'taxonomy' => 'wptests_tax',
+				'parent'   => $t3,
+			)
+		);
+
+		$q = new WP_Term_Query(
+			array(
+				'taxonomy'   => 'wptests_tax',
+				'childless'  => true,
+				'child_of'   => $t1,
+				'hide_empty' => false,
+				'fields'     => 'ids',
+			)
+		);
+
+		$this->assertEqualSets( array( $t2 ), $q->terms );
+	}
 }