diff --git a/CHANGES.rst b/CHANGES.rst
index a314898..2340f3d 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -7,6 +7,8 @@ Changelog
 - Add a final `.` at end of help title message displayed when hovering the
   `Signed/Not signed` icon in the UI.
   [gbastien]
+- Improved file ordering in session.
+  [chris-adam]
 
 1.0.0 (2026-08-14)
 ------------------
diff --git a/src/imio/esign/adapters.py b/src/imio/esign/adapters.py
index a1118ba..16b2197 100644
--- a/src/imio/esign/adapters.py
+++ b/src/imio/esign/adapters.py
@@ -20,6 +20,16 @@ def get_context_uid(self):
         return None
 
 
+class DefaultItemOrderProvider(object):
+    """Default adapter that orders items by their position in the context container."""
+
+    def __init__(self, context):
+        self.context = context
+
+    def get_item_order(self):
+        return {a.UID(): idx for idx, a in enumerate(self.context.values())}
+
+
 class FilesBelongingToAGivenSession(object):
     def __init__(self, context):
         self.context = context
diff --git a/src/imio/esign/configure.zcml b/src/imio/esign/configure.zcml
index cb1a5e0..de4a599 100644
--- a/src/imio/esign/configure.zcml
+++ b/src/imio/esign/configure.zcml
@@ -23,6 +23,11 @@
     provides=".interfaces.IContextUidProvider"
     for="*" />
 
+  <adapter
+    factory=".adapters.DefaultItemOrderProvider"
+    provides=".interfaces.IItemOrderProvider"
+    for="*" />
+
   <adapter for="*"
     factory=".adapters.FilesBelongingToAGivenSession"
     provides="collective.compoundcriterion.interfaces.ICompoundCriterionFilter"
diff --git a/src/imio/esign/interfaces.py b/src/imio/esign/interfaces.py
index 6f4c48e..1d3e77a 100644
--- a/src/imio/esign/interfaces.py
+++ b/src/imio/esign/interfaces.py
@@ -14,3 +14,12 @@ class IContextUidProvider(Interface):
 
     def get_context_uid():
         """Return the context UID for the file to sign."""
+
+
+class IItemOrderProvider(Interface):
+    """Adapter to provide item ordering within a context."""
+
+    def get_item_order():
+        """Return a dict mapping item UID to sort position (int).
+        Items not in the dict get position -1.
+        """
diff --git a/src/imio/esign/tests/test_adapters.py b/src/imio/esign/tests/test_adapters.py
new file mode 100644
index 0000000..b84ac6a
--- /dev/null
+++ b/src/imio/esign/tests/test_adapters.py
@@ -0,0 +1,37 @@
+# -*- coding: utf-8 -*-
+
+from imio.esign.adapters import DefaultContextUidProvider
+from imio.esign.interfaces import IContextUidProvider
+from imio.esign.interfaces import IItemOrderProvider
+from imio.esign.tests.base import BaseEsignTest
+from plone import api
+from zope.component import getAdapter
+
+
+class TestDefaultContextUidProvider(BaseEsignTest):
+
+    def test_get_context_uid(self):
+        annex = self.portal["folder0"]["annex0"]
+        provider = getAdapter(annex, IContextUidProvider)
+        self.assertEqual(provider.get_context_uid(), self.portal["folder0"].UID())
+
+        class Dummy(object):
+            pass
+
+        provider = DefaultContextUidProvider(Dummy())
+        self.assertIsNone(provider.get_context_uid())
+
+
+class TestDefaultItemOrderProvider(BaseEsignTest):
+
+    def test_get_item_order(self):
+        folder = self.portal["folder0"]
+        provider = getAdapter(folder, IItemOrderProvider)
+        order = provider.get_item_order()
+        children = list(folder.values())
+        for idx, child in enumerate(children):
+            self.assertEqual(order[child.UID()], idx)
+
+        empty = api.content.create(container=self.portal, type="Folder", id="empty-folder")
+        provider = getAdapter(empty, IItemOrderProvider)
+        self.assertEqual(provider.get_item_order(), {})
diff --git a/src/imio/esign/utils.py b/src/imio/esign/utils.py
index 6b69a51..30b55b1 100644
--- a/src/imio/esign/utils.py
+++ b/src/imio/esign/utils.py
@@ -17,6 +17,7 @@
 from imio.esign.config import get_esign_registry_sign_code
 from imio.esign.config import get_esign_registry_vat_number
 from imio.esign.interfaces import IContextUidProvider
+from imio.esign.interfaces import IItemOrderProvider
 from imio.helpers.content import uuidToObject
 from imio.helpers.transmogrifier import get_correct_id
 from imio.helpers.ws import get_auth_token
@@ -162,7 +163,7 @@ def add_files_to_session(  # noqa C901
             # Insert alongside other files from the same context, ordered by position
             context = uuidToObject(context_uid)
             if context is not None:
-                uid_order = {a.UID(): idx for idx, a in enumerate(context.values())}
+                uid_order = getAdapter(context, IItemOrderProvider).get_item_order()
             else:
                 uid_order = {}
             files = session["files"][context_start_idx: context_end_idx + 1]