diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
index be060d0ca20..a0b1a83f9ce 100644
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@@ -34,7 +34,7 @@ matches = "0.1"
 num = "0.1.24"
 rustc-serialize = "0.3"
 selectors = {version = "0.5", features = ["heap_size", "unstable"]}
-serde = "0.6"
+serde = {version = "0.6", features = ["nightly"]}
 serde_macros = "0.6"
 smallvec = "0.1"
 string_cache = {version = "0.2.10", features = ["heap_size"]}