diff --git a/pytorch_lightning/loggers/wandb.py b/pytorch_lightning/loggers/wandb.py
index 4e357806579f67..d0a139266ca069 100644
--- a/pytorch_lightning/loggers/wandb.py
+++ b/pytorch_lightning/loggers/wandb.py
@@ -125,6 +125,7 @@ def watch(self, model: nn.Module, log: str = 'gradients', log_freq: int = 100):
     @rank_zero_only
     def log_hyperparams(self, params: Union[Dict[str, Any], Namespace]) -> None:
         params = self._convert_params(params)
+        params = self._flatten_dict(params)
         self.experiment.config.update(params, allow_val_change=True)
 
     @rank_zero_only