diff --git a/src/lib.rs b/src/lib.rs
index 895ce8a..1c56e09 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -195,7 +195,7 @@ impl PartialEq for ASN1Block {
 }
 
 /// An ASN.1 OID.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct OID(Vec<BigUint>);
 
 impl OID {