diff --git a/harmonyqml/backend/model/sort_filter_proxy.py b/harmonyqml/backend/model/sort_filter_proxy.py
index 4069676a..757108ca 100644
--- a/harmonyqml/backend/model/sort_filter_proxy.py
+++ b/harmonyqml/backend/model/sort_filter_proxy.py
@@ -1,7 +1,8 @@
-from typing import Dict
+from typing import Any, Callable, Dict, Optional
 
 from PyQt5.QtCore import (
-    QObject, QSortFilterProxyModel, Qt, pyqtProperty, pyqtSignal, pyqtSlot
+    QModelIndex, QObject, QSortFilterProxyModel, Qt, pyqtProperty, pyqtSignal,
+    pyqtSlot
 )
 
 from .list_model import ListModel
@@ -15,9 +16,10 @@ class SortFilterProxy(QSortFilterProxyModel):
 
     def __init__(self,
                  source_model:   ListModel,
-                 sort_by_role:   str,
-                 filter_by_role: str,
+                 sort_by_role:   str  = "",
+                 filter_by_role: str  = "",
                  ascending:      bool = True,
+                 sort_func:      Optional[Callable[[Any, Any], bool]] = None,
                  parent:         QObject = None) -> None:
         super().__init__(parent)
         self.setDynamicSortFilter(False)
@@ -28,6 +30,8 @@ class SortFilterProxy(QSortFilterProxyModel):
         source_model.countChanged.connect(self.countChanged.emit)
         source_model.changed.connect(self._apply_sort)
 
+        self.sort_func = sort_func
+
         self._sort_by_role = ""
         self.sortByRole    = sort_by_role
         self.ascending     = ascending
@@ -83,9 +87,15 @@ class SortFilterProxy(QSortFilterProxyModel):
         numbers = self.sourceModel().roleNumbers()
         try:
             self.setSortRole(numbers[self.sortByRole])
+        except (AttributeError, KeyError):
+            # Model doesn't have its roles set yet (empty model), or no
+            # self.sortByRole passed
+            pass
+
+        try:
             self.setFilterRole(numbers[self.filterByRole])
-        except KeyError:
-            pass  # Model doesn't have its roles set yet (empty model)
+        except (AttributeError, KeyError):
+            pass
 
 
     def _apply_sort(self) -> None:
@@ -93,6 +103,24 @@ class SortFilterProxy(QSortFilterProxyModel):
         self.sort(0, order)
 
 
+    # Sorting/filtering implementations
+
+
+    def lessThan(self, source_left: QModelIndex, source_right: QModelIndex
+                ) -> bool:
+        left  = self.sourceModel()[source_left.row()]
+        right = self.sourceModel()[source_right.row()]
+
+        if self.sort_func:
+            return self.sort_func(left, right)
+
+        role = self.sortByRole
+        try:
+            return getattr(left, role) < getattr(right, role)
+        except TypeError:  # comparison between the two types not supported
+            return False
+
+
     # The rest
 
     def __repr__(self) -> str:
diff --git a/harmonyqml/backend/pyqt_future.py b/harmonyqml/backend/pyqt_future.py
index 957bb88a..c9cbcd3d 100644
--- a/harmonyqml/backend/pyqt_future.py
+++ b/harmonyqml/backend/pyqt_future.py
@@ -39,6 +39,11 @@ class PyQtFuture(QObject):
         )
 
 
+    def __lt__(self, other: "PyQtFuture") -> bool:
+        # This is to allow sorting, e.g. from SortFilterProxy.lessThan()
+        return self.value < other.value
+
+
     @pyqtSlot()
     def cancel(self):
         self.future.cancel()
diff --git a/harmonyqml/backend/signal_manager.py b/harmonyqml/backend/signal_manager.py
index 694106ac..1d08f20d 100644
--- a/harmonyqml/backend/signal_manager.py
+++ b/harmonyqml/backend/signal_manager.py
@@ -153,6 +153,11 @@ class SignalManager(QObject):
             )
 
 
+    def _members_sort_func(self, left: RoomMember, right: RoomMember) -> bool:
+        users = self.backend.users
+        return users[left.userId].displayName < users[right.userId].displayName
+
+
     def onRoomInvited(self,
                       client:  Client,
                       room_id: str,
@@ -169,8 +174,8 @@ class SignalManager(QObject):
         members        = ListModel()
         sorted_members = SortFilterProxy(
             source_model   = members,
-            sort_by_role   = "userId",  # TODO
-            filter_by_role = "userId",
+            filter_by_role = "displayName",
+            sort_func      = self._members_sort_func,
         )
 
         categories["Invites"].rooms.upsert(
@@ -209,8 +214,8 @@ class SignalManager(QObject):
         members        = ListModel()
         sorted_members = SortFilterProxy(
             source_model   = members,
-            sort_by_role   = "userId",  # TODO
-            filter_by_role = "userId",
+            filter_by_role = "displayName",
+            sort_func      = self._members_sort_func,
         )
 
         categories["Rooms"].rooms.upsert(
@@ -252,8 +257,8 @@ class SignalManager(QObject):
         members        = ListModel()
         sorted_members = SortFilterProxy(
             source_model   = members,
-            sort_by_role   = "userId",  # TODO
-            filter_by_role = "userId",
+            sort_by_role   = "displayName",
+            filter_by_role = "displayName",
         )
 
         categories["Left"].rooms.upsert(
diff --git a/harmonyqml/components/Chat/RoomSidePane/MemberDelegate.qml b/harmonyqml/components/Chat/RoomSidePane/MemberDelegate.qml
index 637bbc8c..3803a525 100644
--- a/harmonyqml/components/Chat/RoomSidePane/MemberDelegate.qml
+++ b/harmonyqml/components/Chat/RoomSidePane/MemberDelegate.qml
@@ -7,7 +7,7 @@ MouseArea {
     width: memberList.width
     height: childrenRect.height
 
-    property var member: Backend.users.get(modelData)
+    property var member: Backend.users.get(userId)
 
     HRowLayout {
         width: parent.width