diff --git a/druntime/src/core/stdc/config.d b/druntime/src/core/stdc/config.d
index 7c5b53df1ff4..f52e6d05b484 100644
--- a/druntime/src/core/stdc/config.d
+++ b/druntime/src/core/stdc/config.d
@@ -213,6 +213,37 @@ else version (WASI)
         alias cpp_ulonglong = ulong;
     }
 }
+else version (WebAssembly)
+{
+    static if ( (void*).sizeof > int.sizeof )
+    {
+        enum __c_longlong  : long;
+        enum __c_ulonglong : ulong;
+
+        alias c_long = long;
+        alias c_ulong = ulong;
+
+        alias cpp_long = long;
+        alias cpp_ulong = ulong;
+
+        alias cpp_longlong = __c_longlong;
+        alias cpp_ulonglong = __c_ulonglong;
+    }
+    else
+    {
+        enum __c_long  : int;
+        enum __c_ulong : uint;
+
+        alias c_long = int;
+        alias c_ulong = uint;
+
+        alias cpp_long = __c_long;
+        alias cpp_ulong = __c_ulong;
+
+        alias cpp_longlong = long;
+        alias cpp_ulonglong = ulong;
+    }
+}
 
 version (GNU)
     alias c_long_double = real;