diff --git a/keras_tuner/backend/config.py b/keras_tuner/backend/config.py
index 439a2e041..1665a32a0 100644
--- a/keras_tuner/backend/config.py
+++ b/keras_tuner/backend/config.py
@@ -12,15 +12,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import keras
+import os
 
 
-def _multi_backend():
+if os.environ.get("TF_USE_LEGACY_KERAS", None) in ("true", "True", "1"):
+    from tensorflow as keras
+    _MULTI_BACKEND = False
+else:
+    import keras
     version_fn = getattr(keras, "version", None)
-    return version_fn and version_fn().startswith("3.")
-
-
-_MULTI_BACKEND = _multi_backend()
+    _MULTI_BACKEND = version_fn and version_fn().startswith("3.")
 
 
 def multi_backend():