diff --git a/generator/templates/api_cpp.h b/generator/templates/api_cpp.h
index 4d2a072174..12ce3405e7 100644
--- a/generator/templates/api_cpp.h
+++ b/generator/templates/api_cpp.h
@@ -25,6 +25,8 @@
 #include "dawn/{{api}}_cpp_chained_struct.h"
 #include "dawn/EnumClassBitmasks.h"
 #include <cmath>
+#include <cstddef>
+#include <cstdint>
 
 namespace {{metadata.namespace}} {
 
diff --git a/generator/templates/api_cpp_chained_struct.h b/generator/templates/api_cpp_chained_struct.h
index 59a0fd0c19..8c0af4a382 100644
--- a/generator/templates/api_cpp_chained_struct.h
+++ b/generator/templates/api_cpp_chained_struct.h
@@ -20,6 +20,9 @@
 #ifndef {{API}}_CPP_CHAINED_STRUCT_H_
 #define {{API}}_CPP_CHAINED_STRUCT_H_
 
+#include <cstddef>
+#include <cstdint>
+
 // This header file declares the ChainedStruct structures separately from the {{metadata.api}}
 // headers so that dependencies can directly extend structures without including the larger header
 // which exposes capabilities that may require correctly set proc tables.