diff --git a/ecdsa/Cargo.toml b/ecdsa/Cargo.toml
index cb804e15..a1bc102e 100644
--- a/ecdsa/Cargo.toml
+++ b/ecdsa/Cargo.toml
@@ -39,7 +39,7 @@ alloc = ["elliptic-curve/alloc", "signature/alloc", "spki/alloc"]
 std = ["alloc", "elliptic-curve/std"]
 
 algorithm = ["dep:rfc6979", "digest", "elliptic-curve/arithmetic"]
-dev = ["algorithm", "digest/dev", "elliptic-curve/dev"]
+dev = ["algorithm", "der", "digest/dev", "elliptic-curve/dev"]
 der = ["dep:der"]
 digest = ["dep:digest", "elliptic-curve/digest", "signature/digest"]
 getrandom = ["elliptic-curve/getrandom"]