diff --git a/include/secp256k1.h b/include/secp256k1.h
index 5c109f4852383..91cdd3672f597 100644
--- a/include/secp256k1.h
+++ b/include/secp256k1.h
@@ -533,7 +533,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_create(
  *
  *  Returns: 1 always
  *  Args:   ctx:        pointer to a context object
- *  In/Out: pubkey:     pointer to the public key to be negated (cannot be NULL)
+ *  In/Out: seckey:     pointer to the 32-byte private key to be negated (cannot be NULL)
  */
 SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_negate(
     const secp256k1_context* ctx,