diff --git a/nerfstudio/engine/trainer.py b/nerfstudio/engine/trainer.py
index 68b026c13..9b4d6d8a1 100644
--- a/nerfstudio/engine/trainer.py
+++ b/nerfstudio/engine/trainer.py
@@ -82,7 +82,7 @@ class TrainerConfig(ExperimentConfig):
     """Path to checkpoint file."""
     log_gradients: bool = False
     """Optionally log gradients during training"""
-    gradient_accumulation_steps: Dict = field(default_factory=lambda: {})
+    gradient_accumulation_steps: Dict[str, int] = field(default_factory=lambda: {})
     """Number of steps to accumulate gradients over. Contains a mapping of {param_group:num}"""