diff --git a/Cargo.toml b/Cargo.toml
index ab2add6..7e134e1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,7 +16,7 @@ path = "src/lib.rs"
 
 [features]
 default = [ "std" ]
-std = []
+std = [ "serde/std" ]
 
 # Note: English is the standard for bip39 so always included
 chinese-simplified = []
@@ -44,7 +44,7 @@ bitcoin_hashes = "0.9.4"
 unicode-normalization = "=0.1.9"
 
 rand = { version = "0.6.0", optional = true }
-serde = { version = "1.0", optional = true }
+serde = { version = "1.0", default-features = false, optional = true }
 
 [dev-dependencies]
 rand = { version = "0.6.0", optional = false }