diff --git a/pyquil/operator_estimation.py b/pyquil/operator_estimation.py
index c5d57b9b6..cc3af0091 100644
--- a/pyquil/operator_estimation.py
+++ b/pyquil/operator_estimation.py
@@ -218,7 +218,7 @@ def to_json(fn, obj):
     See :py:func:`read_json`.
     """
     with open(fn, 'w') as f:
-        json.dump(obj, f, cls=OperatorEncoder, indent=2)
+        json.dump(obj, f, cls=OperatorEncoder, indent=2, ensure_ascii=False)
     return fn