diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 5719ee2d16..6fee54c7a4 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -24,6 +24,9 @@ Fixed
 * Fix ``TypeError`` when displaying help for actions whose parameters have no ``description`` key. #6375
 * Fix utf-8 encode before checking paramter max size #6352
 * Fix stuck running workflow tasks #6398 (by @guzzijones12@gmail.com)
+* Improve workflow cancellation performance for tasks with a large with-items fan-out by
+  batch-fetching child action executions and using a server-side count in ``is_children_active``
+  instead of loading every child execution document into memory. (by @guzzijones12@gmail.com)
 
 Changed
 ~~~~~~~
diff --git a/contrib/runners/orquesta_runner/orquesta_runner/orquesta_runner.py b/contrib/runners/orquesta_runner/orquesta_runner/orquesta_runner.py
index 717ec979c4..9903938585 100644
--- a/contrib/runners/orquesta_runner/orquesta_runner/orquesta_runner.py
+++ b/contrib/runners/orquesta_runner/orquesta_runner/orquesta_runner.py
@@ -276,13 +276,21 @@ def cancel(self):
             }
 
         # Request cancellation of tasks that are workflows and still running.
-        for child_ex_id in self.execution.children:
-            child_ex = ex_db_access.ActionExecution.get(id=child_ex_id)
-            if self.task_cancelable(child_ex):
-                ac_svc.request_cancellation(
-                    lv_db_access.LiveAction.get(id=child_ex.liveaction_id),
-                    self.context.get("user", None),
-                )
+        # Batch-fetch the child action executions in a single query instead of
+        # issuing one get() per child. For a task with a large with-items
+        # fan-out the per-child gets add up to thousands of serial DB
+        # round-trips during cancellation.
+        child_ex_ids = self.execution.children
+
+        if child_ex_ids:
+            child_exs = ex_db_access.ActionExecution.query(id__in=child_ex_ids)
+
+            for child_ex in child_exs:
+                if self.task_cancelable(child_ex):
+                    ac_svc.request_cancellation(
+                        lv_db_access.LiveAction.get(id=child_ex.liveaction_id),
+                        self.context.get("user", None),
+                    )
 
         status = (
             ac_const.LIVEACTION_STATUS_CANCELING
diff --git a/lockfiles/st2.lock b/lockfiles/st2.lock
index 546f12698e..7a9f94672c 100644
--- a/lockfiles/st2.lock
+++ b/lockfiles/st2.lock
@@ -3085,7 +3085,7 @@
           "artifacts": [
             {
               "algorithm": "sha256",
-              "hash": "491767e81c1bb11a54fb68d1a24119bdeede593a2beccca5bc09bfed36fdb35c",
+              "hash": "b9feb1769b48102061fe4fc59b2f5ad600bc2ac0b55cf12ef5fe49464ac0d230",
               "url": "git+https://github.com/StackStorm/orquesta.git"
             }
           ],
diff --git a/st2common/st2common/services/action.py b/st2common/st2common/services/action.py
index d5f35eb204..3383ba5f2d 100644
--- a/st2common/st2common/services/action.py
+++ b/st2common/st2common/services/action.py
@@ -546,19 +546,21 @@ def is_children_active(liveaction_id):
     if execution_db.runner["name"] not in action_constants.WORKFLOW_RUNNER_TYPES:
         return False
 
-    children_execution_dbs = ActionExecution.query(parent=str(execution_db.id))
-
     inactive_statuses = action_constants.LIVEACTION_COMPLETED_STATES + [
         action_constants.LIVEACTION_STATUS_PAUSED,
         action_constants.LIVEACTION_STATUS_PENDING,
     ]
 
-    completed = [
-        child_exec_db.status in inactive_statuses
-        for child_exec_db in children_execution_dbs
-    ]
+    # Count children whose status is not inactive with a server-side query
+    # instead of loading every child execution document into memory. This
+    # matters for tasks with a large with-items fan-out, where the parent can
+    # have thousands of children.
+    active_children_count = ActionExecution.count(
+        parent=str(execution_db.id),
+        status__nin=inactive_statuses,
+    )
 
-    return not all(completed)
+    return active_children_count > 0
 
 
 def _cleanup_liveaction(liveaction):