diff --git a/src/CppAst/CppModelBuilder.cs b/src/CppAst/CppModelBuilder.cs
index 3b20da6..9665691 100644
--- a/src/CppAst/CppModelBuilder.cs
+++ b/src/CppAst/CppModelBuilder.cs
@@ -1792,7 +1792,7 @@ private CppType GetCppTypeInternal(CXCursor cursor, CXType type, CXCursor parent
                     return CppPrimitiveType.UnsignedInt;
 
                 case CXTypeKind.CXType_ULong:
-                    return CppPrimitiveType.UnsignedInt;
+                    return RuntimeInformation.IsOSPlatform(OSPlatform.Linux) ? CppPrimitiveType.UnsignedLongLong : CppPrimitiveType.UnsignedInt;
 
                 case CXTypeKind.CXType_ULongLong:
                     return CppPrimitiveType.UnsignedLongLong;