diff --git a/smt/surrogate_models/sgp.py b/smt/surrogate_models/sgp.py
index 728d6b7ae..dd366d7ec 100644
--- a/smt/surrogate_models/sgp.py
+++ b/smt/surrogate_models/sgp.py
@@ -50,6 +50,13 @@ def _initialize(self):
             desc="Gaussian noise on observed training data",
             types=(list, np.ndarray),
         )
+        declare(
+            "hyper_opt",
+            "Cobyla",
+            values=("Cobyla"),
+            desc="Optimiser for hyperparameters optimisation",
+            types=str,
+        )
         declare(
             "eval_noise",
             True,  # for SGP evaluate noise by default