diff --git a/src/wp-includes/class-wp-term-query.php b/src/wp-includes/class-wp-term-query.php
index 79ec315c4f..74386bc9ab 100644
--- a/src/wp-includes/class-wp-term-query.php
+++ b/src/wp-includes/class-wp-term-query.php
@@ -474,7 +474,10 @@ class WP_Term_Query {
 			$this->sql_clauses['where']['exclusions'] = preg_replace( '/^\s*AND\s*/', '', $exclusions );
 		}
 
-		if ( ! empty( $args['name'] ) ) {
+		if (
+			( ! empty( $args['name'] ) ) ||
+			( is_string( $args['name'] ) && 0 !== strlen( $args['name'] ) )
+		) {
 			$names = (array) $args['name'];
 			foreach ( $names as &$_name ) {
 				// `sanitize_term_field()` returns slashed data.
@@ -484,7 +487,10 @@ class WP_Term_Query {
 			$this->sql_clauses['where']['name'] = "t.name IN ('" . implode( "', '", array_map( 'esc_sql', $names ) ) . "')";
 		}
 
-		if ( ! empty( $args['slug'] ) ) {
+		if (
+			( ! empty( $args['slug'] ) ) ||
+			( is_string( $args['slug'] ) && 0 !== strlen( $args['slug'] ) )
+		) {
 			if ( is_array( $args['slug'] ) ) {
 				$slug = array_map( 'sanitize_title', $args['slug'] );
 				$this->sql_clauses['where']['slug'] = "t.slug IN ('" . implode( "', '", $slug ) . "')";
diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index a7c6a4d267..f8bc57d039 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -835,6 +835,15 @@ function get_term_by( $field, $value, $taxonomy = '', $output = OBJECT, $filter
 		return false;
 	}
 
+	// No need to perform a query for empty 'slug' or 'name'.
+	if ( 'slug' === $field || 'name' === $field ) {
+		$value = (string) $value;
+
+		if ( 0 === strlen( $value ) ) {
+			return false;
+		}
+	}
+
 	if ( 'id' === $field || 'term_id' === $field ) {
 		$term = get_term( (int) $value, $taxonomy, $output, $filter );
 		if ( is_wp_error( $term ) || null === $term ) {
diff --git a/tests/phpunit/tests/term/getTermBy.php b/tests/phpunit/tests/term/getTermBy.php
index 1e02a7afa6..4adda74f5a 100644
--- a/tests/phpunit/tests/term/getTermBy.php
+++ b/tests/phpunit/tests/term/getTermBy.php
@@ -205,4 +205,48 @@ class Tests_Term_GetTermBy extends WP_UnitTestCase {
 
 		$this->assertEquals( 0, $action->get_call_count() );
 	}
+
+	/**
+	 * @ticket 21760
+	 */
+	public function test_get_term_by_name_with_string_0() {
+		register_taxonomy( 'wptests_tax', 'post', array( 'hierarchical' => true ) );
+
+		$term_id = $this->factory->term->create( array(
+			'name'     => '0',
+			'taxonomy' => 'wptests_tax',
+		) );
+
+		$found = get_term_by( 'name', '0', 'wptests_tax' );
+		$this->assertSame( $term_id, $found->term_id );
+	}
+
+	/**
+	 * @ticket 21760
+	 */
+	public function test_get_term_by_slug_with_string_0() {
+		register_taxonomy( 'wptests_tax', 'post', array( 'hierarchical' => true ) );
+
+		$term_id = $this->factory->term->create( array(
+			'taxonomy' => 'wptests_tax',
+			'name'     => '0',
+			'slug'     => '0',
+		) );
+
+		$found = get_term_by( 'slug', '0', 'wptests_tax' );
+		$this->assertSame( $term_id, $found->term_id );
+	}
+
+	/**
+	 * @ticket 21760
+	 */
+	public function test_get_term_by_with_empty_string() {
+		register_taxonomy( 'wptests_tax', 'post', array( 'hierarchical' => true ) );
+
+		$found_by_slug = get_term_by( 'slug', '', 'wptests_tax' );
+		$found_by_name = get_term_by( 'name', '', 'wptests_tax' );
+
+		$this->assertFalse( $found_by_slug );
+		$this->assertFalse( $found_by_name );
+	}
 }
diff --git a/tests/phpunit/tests/term/getTerms.php b/tests/phpunit/tests/term/getTerms.php
index 6d199c0747..575e5ca1c0 100644
--- a/tests/phpunit/tests/term/getTerms.php
+++ b/tests/phpunit/tests/term/getTerms.php
@@ -2223,6 +2223,57 @@ class Tests_Term_getTerms extends WP_UnitTestCase {
 		return 'foo';
 	}
 
+	/**
+	 * @ticket 21760
+	 */
+	public function test_with_term_slug_equal_to_string_0() {
+		register_taxonomy( 'wptests_tax', 'post', array( 'hierarchical' => true ) );
+
+		$term_id = self::factory()->term->create( array(
+			'name' => '0',
+			'slug' => '0',
+			'taxonomy' => 'wptests_tax',
+		) );
+
+		$found = get_terms( array(
+			'taxonomy'   => 'wptests_tax',
+			'hide_empty' => 0,
+			'slug'       => '0',
+		) );
+
+		$this->assertEqualSets( array( $term_id ), wp_list_pluck( $found, 'term_id' ) );
+	}
+
+	/**
+	 * @ticket 21760
+	 */
+	public function test_with_multiple_term_slugs_one_equal_to_string_0() {
+		register_taxonomy( 'wptests_tax', 'post', array( 'hierarchical' => true ) );
+
+		$term_id1 = self::factory()->term->create( array(
+			'name'     => '0',
+			'slug'     => '0',
+			'taxonomy' => 'wptests_tax',
+		) );
+
+		$term_id2 = self::factory()->term->create( array(
+			'name'     => 'Test',
+			'slug'     => 'test',
+			'taxonomy' => 'wptests_tax',
+		) );
+
+		$found = get_terms( array(
+			'taxonomy'   => 'wptests_tax',
+			'hide_empty' => 0,
+			'slug'       => array(
+				'0',
+				'test',
+			),
+		) );
+
+		$this->assertEqualSets( array( $term_id1, $term_id2 ), wp_list_pluck( $found, 'term_id' ) );
+	}
+
 	protected function create_hierarchical_terms_and_posts() {
 		$terms = array();