diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index 7d341edae4..c898cbf18a 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -1649,7 +1649,6 @@ function get_terms( $taxonomies, $args = '' ) {
 
 	// Save queries by not crawling the tree in the case of multiple taxes or a flat tax.
 	if ( ! $single_taxonomy || ! is_taxonomy_hierarchical( reset( $taxonomies ) ) ) {
-		$args['child_of'] = false;
 		$args['hierarchical'] = false;
 		$args['pad_counts'] = false;
 	}
diff --git a/tests/phpunit/tests/term/getTerms.php b/tests/phpunit/tests/term/getTerms.php
index 6dcc076837..3656b1aa7a 100644
--- a/tests/phpunit/tests/term/getTerms.php
+++ b/tests/phpunit/tests/term/getTerms.php
@@ -173,6 +173,28 @@ class Tests_Term_getTerms extends WP_UnitTestCase {
 		$this->assertEmpty( $wpdb->last_error );
 	}
 
+	/**
+	 * @ticket 30275
+	 */
+	public function test_exclude_with_hierarchical_true_for_non_hierarchical_taxonomy() {
+		register_taxonomy( 'wptests_tax', 'post' );
+
+		$terms = $this->factory->term->create_many( 2, array(
+			'taxonomy' => 'wptests_tax',
+		) );
+
+		$found = get_terms( 'wptests_tax', array(
+			'taxonomy' => 'wptests_tax',
+			'hide_empty' => false,
+			'exclude_tree' => array( $terms[0] ),
+			'hierarchical' => true,
+		) );
+
+		$this->assertEquals( array( $terms[1] ), wp_list_pluck( $found, 'term_id' ) );
+
+		_unregister_taxonomy( 'wptests_tax' );
+	}
+
 	/**
 	 * @ticket 25710
 	 */