diff --git a/tests/unit/stylo/lib.rs b/tests/unit/stylo/lib.rs
index 45b9d63a9fd..0b7da6ad03c 100644
--- a/tests/unit/stylo/lib.rs
+++ b/tests/unit/stylo/lib.rs
@@ -13,6 +13,7 @@ extern crate selectors;
 extern crate style_traits;
 
 mod sanity_checks;
+#[cfg(target_pointer_width = "64")]
 mod size_of;
 mod specified_values;
 
diff --git a/tests/unit/stylo/specified_values.rs b/tests/unit/stylo/specified_values.rs
index fa71afe0396..d373966c41f 100644
--- a/tests/unit/stylo/specified_values.rs
+++ b/tests/unit/stylo/specified_values.rs
@@ -4,7 +4,7 @@
 
 use style;
 
-#[test]
+#[cfg(all(test, target_pointer_width = "64"))]
 fn size_of_specified_values() {
     use std::mem::size_of;
     let threshold = 24;