diff --git a/lib/ansible/plugins/inventory/netbox.py b/lib/ansible/plugins/inventory/netbox.py
index d8ad3dda9e5..ac4f99c845b 100644
--- a/lib/ansible/plugins/inventory/netbox.py
+++ b/lib/ansible/plugins/inventory/netbox.py
@@ -355,11 +355,10 @@ class InventoryModule(BaseInventoryPlugin, Constructable):
         if self.query_filters:
             query_parameters.extend(filter(lambda x: x,
                                            map(self.validate_query_parameters, self.query_filters)))
-        self.device_url = self.api_endpoint + "/api/dcim/devices/" + "?" + urlencode(query_parameters)
-        self.virtual_machines_url = "".join([self.api_endpoint,
-                                             "/api/virtualization/virtual-machines/",
-                                             "?",
-                                             urlencode(query_parameters)])
+        self.device_url = urljoin(self.api_endpoint,
+                                  "/api/dcim/devices/?" + urlencode(query_parameters))
+        self.virtual_machines_url = urljoin(self.api_endpoint,
+                                            "/api/virtualization/virtual-machines/?" + urlencode(query_parameters))
 
     def fetch_hosts(self):
         return chain(