diff --git a/.editorconfig b/.editorconfig
index 76ff616..35ba4d8 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -15,6 +15,9 @@ indent_style = tab
 space_around_brackets = true
 indent_size = 4
 
+[*.php]
+indent_style = space
+
 [{.jshintrc,*.json,*.yml}]
 indent_style = space
 indent_size = 2
diff --git a/src/Base/RestAPI/Controllers/BaseController.php b/src/Base/RestAPI/Controllers/BaseController.php
index f887ac8..a199ba1 100644
--- a/src/Base/RestAPI/Controllers/BaseController.php
+++ b/src/Base/RestAPI/Controllers/BaseController.php
@@ -118,4 +118,32 @@ protected function defaultTaxonomyParamIsValid(WP_REST_Request $request, string
 
         return true;
     }
+
+    protected function getOrderClause(string $orderBy, string $order): array
+    {
+        $orderArray = [];
+        $orderByParts = explode(',', $orderBy);
+        $orderParts = explode(',', $order);
+
+        // Empty string results in array with one empty value, we ignore that.
+        if (!array_filter($orderByParts)) {
+            return [];
+        }
+
+        // Single orderby value, return simple array.
+        if (count($orderByParts) === 1) {
+            return [
+                'orderby' => trim($orderByParts[0]),
+                'order' => strtoupper(trim($orderParts[0] ?? 'ASC')),
+            ];
+        }
+
+        // Multiple orderby values, return associative array.
+        foreach ($orderByParts as $index => $orderByPart) {
+            $orderValue = $orderParts[$index] ?? $orderParts[0] ?? 'ASC';
+            $orderArray[trim($orderByPart)] = strtoupper(trim($orderValue));
+        }
+
+        return ['orderby' => $orderArray];
+    }
 }
diff --git a/src/Base/RestAPI/Controllers/ItemController.php b/src/Base/RestAPI/Controllers/ItemController.php
index a606b5d..afe3ec0 100644
--- a/src/Base/RestAPI/Controllers/ItemController.php
+++ b/src/Base/RestAPI/Controllers/ItemController.php
@@ -25,15 +25,15 @@ class ItemController extends BaseController
      */
     public function getItems(WP_REST_Request $request): array
     {
+        $orderBy = $request->get_param('orderby') ?? 'post_date,ID';
+        $order = $request->get_param('order') ?? 'DESC,DESC';
+
         $parameters = $this->convertParameters($request->get_params());
         $items = (new Item())
             ->query(apply_filters('owc/pdc/rest-api/items/query', $this->getPaginatorParams($request)))
             ->query($parameters)
             ->query($this->excludeInactiveItemsQuery())
-            ->query(['orderby' => [
-                'post_date' => 'DESC',
-                'ID' => 'DESC',
-            ]]);
+            ->query($this->getOrderClause($orderBy, $order));
 
         if ($this->plugin->settings->useShowOn() && $this->showOnParamIsValid($request)) {
             $items->filterSource($request->get_param('source'));
diff --git a/src/Base/RestAPI/Controllers/SubthemaController.php b/src/Base/RestAPI/Controllers/SubthemaController.php
index cb0cb4c..629ff46 100644
--- a/src/Base/RestAPI/Controllers/SubthemaController.php
+++ b/src/Base/RestAPI/Controllers/SubthemaController.php
@@ -20,11 +20,13 @@ class SubthemaController extends BaseController
      */
     public function getSubthemas(WP_REST_Request $request): array
     {
+        $orderBy = $request->get_param('orderby') ?? 'name';
+        $order = $request->get_param('order') ?? 'ASC';
+
         $items = (new Subthema())
             ->query(apply_filters('owc/pdc/rest-api/subthemas/query', $this->getPaginatorParams($request)))
+            ->query($this->getOrderClause($orderBy, $order))
             ->query([
-                'order' => 'ASC',
-                'orderby' => 'name',
                 'post_status' => $this->getPostStatus($request)
             ]);
 
diff --git a/src/Base/RestAPI/Controllers/ThemaController.php b/src/Base/RestAPI/Controllers/ThemaController.php
index ef20ef5..71f924e 100644
--- a/src/Base/RestAPI/Controllers/ThemaController.php
+++ b/src/Base/RestAPI/Controllers/ThemaController.php
@@ -25,9 +25,8 @@ public function getThemas(WP_REST_Request $request): array
 
         $items = (new Thema())
             ->query(apply_filters('owc/pdc/rest-api/themas/query', $this->getPaginatorParams($request)))
+            ->query($this->getOrderClause($orderBy, $order))
             ->query([
-                'order' => $order,
-                'orderby' => $orderBy,
                 'post_status' => $this->getPostStatus($request)
             ])
             ->hide(['items']);