diff --git a/lib/endpoints/class-wp-rest-posts-terms-controller.php b/lib/endpoints/class-wp-rest-posts-terms-controller.php
index <HASH>..<HASH> 100644
--- a/lib/endpoints/class-wp-rest-posts-terms-controller.php
+++ b/lib/endpoints/class-wp-rest-posts-terms-controller.php
@@ -126,8 +126,9 @@ class WP_REST_Posts_Terms_Controller extends WP_REST_Controller {
 		if ( is_wp_error( $is_request_valid ) ) {
 			return $is_request_valid;
 		}
-
-		$tt_ids = wp_set_object_terms( $post->ID, $term_id, $this->taxonomy, true );
+		
+		$term = get_term_by('term_taxonomy_id', $term_id, $this->taxonomy);
+		$tt_ids = wp_set_object_terms( $post->ID, $term->term_id, $this->taxonomy, true );
 
 		if ( is_wp_error( $tt_ids ) ) {
 			return $tt_ids;
#<I>: When associating terms to posts, align WP-API use of term_taxonomy_id with WP core's use of term_id.