diff --git a/rust/hgcli/pyoxidizer.bzl b/rust/hgcli/pyoxidizer.bzl
--- a/rust/hgcli/pyoxidizer.bzl
+++ b/rust/hgcli/pyoxidizer.bzl
@@ -255,7 +255,7 @@
         path = "defaultrc/editor.rc",
     )
 
-    wix = WiXInstaller("hg", "%s-%s.msi" % (MSI_NAME, VERSION))
+    wix = WiXInstaller("hg", "%s-%s.msi" % (MSI_NAME, VERSION), arch = platform)
 
     # Materialize files in the manifest to the install layout.
     wix.add_install_files(manifest)