diff --git a/includes/rest-api/class-acf-rest-api.php b/includes/rest-api/class-acf-rest-api.php
index d06611f3..98e05488 100644
--- a/includes/rest-api/class-acf-rest-api.php
+++ b/includes/rest-api/class-acf-rest-api.php
@@ -66,6 +66,13 @@ public function register_field() {
 
 		$base = $this->request->object_sub_type;
 
+		// WordPress term controllers use the schema title as the object type for
+		// additional REST fields. For built-in tags, the taxonomy is "post_tag"
+		// but the REST object type is "tag".
+		if ( 'term' === $this->request->object_type && 'post_tag' === $base ) {
+			$base = 'tag';
+		}
+
 		// If the object sub type ($post_type, $taxonomy, 'user') cannot be determined from the current request,
 		// we don't know what endpoint to register the field against. Bail if that is the case.
 		if ( ! $base ) {
@@ -218,7 +225,12 @@ public function load_fields( $object, $field_name, $request, $object_sub_type )
 			return $fields;
 		}
 
-		$object_sub_type = str_replace( '-revision', '', $object_sub_type );
+		// Preserve the taxonomy slug for ACF field-group matching.
+		if ( 'term' === $object_type && $this->request->object_sub_type ) {
+			$object_sub_type = $this->request->object_sub_type;
+		} else {
+			$object_sub_type = str_replace( '-revision', '', $object_sub_type );
+		}
 
 		// Get all field groups for the current object.
 		$field_groups = $this->get_field_groups_by_id( $object_id, $object_type, $object_sub_type );
@@ -285,6 +297,11 @@ public function update_fields( $data, $object, $property, $request, $object_sub_
 			);
 		}
 
+		// Preserve the taxonomy slug for ACF field-group matching.
+		if ( 'term' === $object_type && $this->request->object_sub_type ) {
+			$object_sub_type = $this->request->object_sub_type;
+		}
+
 		// Determine the ACF selector for the current object.
 		$post_id = $this->make_identifier( $object_id, $object_type );