diff --git a/tokio/Cargo.toml b/tokio/Cargo.toml
index 3e6b95784b6..a60f348fb3c 100644
--- a/tokio/Cargo.toml
+++ b/tokio/Cargo.toml
@@ -94,7 +94,7 @@ pin-project-lite = "0.2.0"
 # Everything else is optional...
 bytes = { version = "1.0.0", optional = true }
 memchr = { version = "2.2", optional = true }
-mio = { version = "0.8.1", optional = true }
+mio = { version = "0.8.1", optional = true, default-features = false }
 socket2 = { version = "0.4.4", optional = true, features = [ "all" ] }
 num_cpus = { version = "1.8.0", optional = true }
 parking_lot = { version = "0.12.0", optional = true }