diff --git a/atst/models/task_order.py b/atst/models/task_order.py
index ac860129..d1d32206 100644
--- a/atst/models/task_order.py
+++ b/atst/models/task_order.py
@@ -86,6 +86,8 @@ class TaskOrder(Base, mixins.TimestampsMixin):
             self._csp_estimate = Attachment.attach(
                 new_csp_estimate, "task_order", self.id
             )
+        elif not new_csp_estimate and self._csp_estimate:
+            self._csp_estimate = None
         else:
             raise TypeError("Could not set csp_estimate with invalid type")
 
diff --git a/tests/models/test_task_order.py b/tests/models/test_task_order.py
index 6cbfc082..447ad258 100644
--- a/tests/models/test_task_order.py
+++ b/tests/models/test_task_order.py
@@ -58,3 +58,11 @@ class TestCSPEstimate:
         to = TaskOrder()
         with pytest.raises(TypeError):
             to.csp_estimate = "invalid"
+
+    def test_removing_estimate(self):
+        attachment = Attachment(filename="sample.pdf", object_name="sample")
+        to = TaskOrder(csp_estimate=attachment)
+        assert to.csp_estimate is not None
+
+        to.csp_estimate = ""
+        assert to.csp_estimate is None