diff --git a/include/tim/vx/graph.h b/include/tim/vx/graph.h
index b7d5c1b..4fb66ab 100644
--- a/include/tim/vx/graph.h
+++ b/include/tim/vx/graph.h
@@ -31,7 +31,7 @@ namespace tim {
 namespace vx {
 
 class Tensor;
-class TensorSpec;
+struct TensorSpec;
 
 class Operation;