diff --git a/src/wp-includes/category-template.php b/src/wp-includes/category-template.php
index 68cd74c8e5..971434baf2 100644
--- a/src/wp-includes/category-template.php
+++ b/src/wp-includes/category-template.php
@@ -904,7 +904,8 @@ function wp_generate_tag_cloud( $tags, $args = '' ) {
 
 	// generate the output links array
 	foreach ( $tags_data as $key => $tag_data ) {
-		$a[] = "<a href='" . esc_url( $tag_data['url'] ) . "' class='" . esc_attr( $tag_data['class'] ) . "' title='" . esc_attr( $tag_data['title'] ) . "' style='font-size: " . esc_attr( str_replace( ',', '.', $tag_data['font_size'] ) . $args['unit'] ) . ";'>" . esc_html( $tag_data['name'] ) . "</a>";
+		$class = $tag_data['class'] . ' tag-link-position-' . ( $key + 1 );
+		$a[] = "<a href='" . esc_url( $tag_data['url'] ) . "' class='" . esc_attr( $class ) . "' title='" . esc_attr( $tag_data['title'] ) . "' style='font-size: " . esc_attr( str_replace( ',', '.', $tag_data['font_size'] ) . $args['unit'] ) . ";'>" . esc_html( $tag_data['name'] ) . "</a>";
 	}
 
 	switch ( $args['format'] ) {
diff --git a/tests/phpunit/tests/term/wpGenerateTagCloud.php b/tests/phpunit/tests/term/wpGenerateTagCloud.php
index 742b3210c1..47a1283657 100644
--- a/tests/phpunit/tests/term/wpGenerateTagCloud.php
+++ b/tests/phpunit/tests/term/wpGenerateTagCloud.php
@@ -78,7 +78,7 @@ class Tests_WP_Generate_Tag_Cloud extends WP_UnitTestCase {
 			'number' => 1,
 			'hide_empty' => false,
 		) );
-		$expected = "<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$term->slug}' class='tag-link-0' title='0 topics' style='font-size: 8pt;'>{$term->name}</a>";
+		$expected = "<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$term->slug}' class='tag-link-0 tag-link-position-1' title='0 topics' style='font-size: 8pt;'>{$term->name}</a>";
 		$this->assertEquals( $expected, wp_generate_tag_cloud( $tags, array(
 			'hide_empty' => false,
 		) ) );
@@ -94,7 +94,7 @@ class Tests_WP_Generate_Tag_Cloud extends WP_UnitTestCase {
 			'format'     => 'array',
 		) );
 
-		$expected = "<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$term->slug}' class='tag-link-0' title='0 topics' style='font-size: 8pt;'>{$term->name}</a>";
+		$expected = "<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$term->slug}' class='tag-link-0 tag-link-position-1' title='0 topics' style='font-size: 8pt;'>{$term->name}</a>";
 		$this->assertEquals( $expected, wp_generate_tag_cloud( $tags, array(
 			'hide_empty' => false,
 		) ) );
@@ -109,7 +109,7 @@ class Tests_WP_Generate_Tag_Cloud extends WP_UnitTestCase {
 			'hide_empty' => false,
 		) );
 
-		$expected = "<ul class='wp-tag-cloud'>\n\t<li><a href='http://" . WP_TESTS_DOMAIN . "/?tag={$term->slug}' class='tag-link-0' title='0 topics' style='font-size: 8pt;'>{$term->name}</a></li>\n</ul>\n";
+		$expected = "<ul class='wp-tag-cloud'>\n\t<li><a href='http://" . WP_TESTS_DOMAIN . "/?tag={$term->slug}' class='tag-link-0 tag-link-position-1' title='0 topics' style='font-size: 8pt;'>{$term->name}</a></li>\n</ul>\n";
 		$this->assertEquals( $expected, wp_generate_tag_cloud( $tags, array(
 			'hide_empty' => false,
 			'format'     => 'list',
@@ -129,10 +129,10 @@ class Tests_WP_Generate_Tag_Cloud extends WP_UnitTestCase {
 			'hide_empty' => false,
 		) );
 
-		$expected = "<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[0]->slug}' class='tag-link-0' title='0 topics' style='font-size: 8pt;'>{$terms[0]->name}</a>\n".
-			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[1]->slug}' class='tag-link-1' title='0 topics' style='font-size: 8pt;'>{$terms[1]->name}</a>\n".
-			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[2]->slug}' class='tag-link-2' title='0 topics' style='font-size: 8pt;'>{$terms[2]->name}</a>\n".
-			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[3]->slug}' class='tag-link-3' title='0 topics' style='font-size: 8pt;'>{$terms[3]->name}</a>";
+		$expected = "<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[0]->slug}' class='tag-link-0 tag-link-position-1' title='0 topics' style='font-size: 8pt;'>{$terms[0]->name}</a>\n".
+			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[1]->slug}' class='tag-link-1 tag-link-position-2' title='0 topics' style='font-size: 8pt;'>{$terms[1]->name}</a>\n".
+			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[2]->slug}' class='tag-link-2 tag-link-position-3' title='0 topics' style='font-size: 8pt;'>{$terms[2]->name}</a>\n".
+			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[3]->slug}' class='tag-link-3 tag-link-position-4' title='0 topics' style='font-size: 8pt;'>{$terms[3]->name}</a>";
 		$this->assertEquals( $expected, wp_generate_tag_cloud( $tags, array(
 			'hide_empty' => false,
 		) ) );
@@ -152,10 +152,10 @@ class Tests_WP_Generate_Tag_Cloud extends WP_UnitTestCase {
 		) );
 
 		$expected = "<ul class='wp-tag-cloud'>\n\t<li>".
-			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[0]->slug}' class='tag-link-0' title='0 topics' style='font-size: 8pt;'>{$terms[0]->name}</a></li>\n\t<li>".
-			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[1]->slug}' class='tag-link-1' title='0 topics' style='font-size: 8pt;'>{$terms[1]->name}</a></li>\n\t<li>".
-			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[2]->slug}' class='tag-link-2' title='0 topics' style='font-size: 8pt;'>{$terms[2]->name}</a></li>\n\t<li>".
-			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[3]->slug}' class='tag-link-3' title='0 topics' style='font-size: 8pt;'>{$terms[3]->name}</a>".
+			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[0]->slug}' class='tag-link-0 tag-link-position-1' title='0 topics' style='font-size: 8pt;'>{$terms[0]->name}</a></li>\n\t<li>".
+			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[1]->slug}' class='tag-link-1 tag-link-position-2' title='0 topics' style='font-size: 8pt;'>{$terms[1]->name}</a></li>\n\t<li>".
+			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[2]->slug}' class='tag-link-2 tag-link-position-3' title='0 topics' style='font-size: 8pt;'>{$terms[2]->name}</a></li>\n\t<li>".
+			"<a href='http://" . WP_TESTS_DOMAIN . "/?tag={$terms[3]->slug}' class='tag-link-3 tag-link-position-4' title='0 topics' style='font-size: 8pt;'>{$terms[3]->name}</a>".
 			"</li>\n</ul>\n";
 
 		$this->assertEquals( $expected, wp_generate_tag_cloud( $tags, array(
@@ -219,6 +219,26 @@ class Tests_WP_Generate_Tag_Cloud extends WP_UnitTestCase {
 		$this->assertContains( "title='2 foo'", $actual[1] );
 	}
 
+	/**
+	 * @ticket 5172
+	 */
+	public function test_should_include_tag_link_position_class() {
+		register_taxonomy( 'wptests_tax', 'post' );
+		$term_ids = self::factory()->term->create_many( 3, array( 'taxonomy' => 'wptests_tax' ) );
+
+		$p = self::factory()->post->create();
+		wp_set_post_terms( $p, $term_ids, 'wptests_tax' );
+
+		$term_objects = get_terms( 'wptests_tax', array(
+			'include' => $term_ids,
+		) );
+
+		$cloud = wp_generate_tag_cloud( $term_objects );
+		preg_match_all( '|tag\-link\-position-([0-9]+)|', $cloud, $matches );
+
+		$this->assertSame( array( 1, 2, 3 ), array_map( 'intval', $matches[1] ) );
+	}
+
 	/**
 	 * Helper method retrieve the created terms.
 	 *