diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index b4346cd858..3a2f272050 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -1016,7 +1016,8 @@ def quantize(self, value):
             return value
 
         context = decimal.getcontext().copy()
-        context.prec = self.max_digits
+        if self.max_digits is not None:
+            context.prec = self.max_digits
         return value.quantize(
             decimal.Decimal('.1') ** self.decimal_places,
             context=context
diff --git a/tests/test_fields.py b/tests/test_fields.py
index 60f02777aa..1cbff99093 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -876,6 +876,18 @@ class TestMinMaxDecimalField(FieldValues):
     )
 
 
+class TestNoMaxDigitsDecimalField(FieldValues):
+    field = serializers.DecimalField(
+        max_value=100, min_value=0,
+        decimal_places=2, max_digits=None
+    )
+    valid_inputs = {
+        '10': Decimal('10.00')
+    }
+    invalid_inputs = {}
+    outputs = {}
+
+
 class TestNoStringCoercionDecimalField(FieldValues):
     """
     Output values for `DecimalField` with `coerce_to_string=False`.