diff --git a/utils/generate_dotnet_channels.js b/utils/generate_dotnet_channels.js
index dab18e5050..e684751729 100644
--- a/utils/generate_dotnet_channels.js
+++ b/utils/generate_dotnet_channels.js
@@ -74,7 +74,7 @@ function mapType(type) {
 }
 
 function nullableSuffix(inner) {
-  if (['int', 'boolean'].includes(inner.ts))
+  if (['int', 'bool'].includes(inner.ts))
     return inner.optional ? '?' : '';
   return '';
 }