diff --git a/app/src/main/java/eu/faircode/email/DaoMessage.java b/app/src/main/java/eu/faircode/email/DaoMessage.java
index 7c52e4cc9d..309f99336f 100644
--- a/app/src/main/java/eu/faircode/email/DaoMessage.java
+++ b/app/src/main/java/eu/faircode/email/DaoMessage.java
@@ -68,12 +68,13 @@ public interface DaoMessage {
             " GROUP BY account.id, CASE WHEN message.thread IS NULL OR NOT :threading THEN message.id ELSE message.thread END" +
             " HAVING :found OR SUM(unified) > 0" +
             " ORDER BY" +
-            " CASE WHEN 'sender' = :sort THEN message.sender ELSE '' END," +
             " CASE" +
-            "  WHEN 'unread' = :sort THEN " + unseen_unified + " > 0" +
-            "  WHEN 'starred' = :sort THEN COUNT(message.id) - " + unflagged_unified + " > 0" +
+            "  WHEN 'unread' = :sort THEN " + unseen_unified + " = 0" +
+            "  WHEN 'starred' = :sort THEN COUNT(message.id) - " + unflagged_unified + " = 0" +
+            "  WHEN 'sender' = :sort THEN LOWER(message.sender)" +
+            "  WHEN 'subject' = :sort THEN LOWER(message.subject)" +
             "  ELSE 0" +
-            " END DESC, message.received DESC")
+            " END, message.received DESC")
     @SuppressWarnings(RoomWarnings.CURSOR_MISMATCH)
     DataSource.Factory<Integer, TupleMessageEx> pagedUnifiedInbox(boolean threading, String sort, boolean snoozed, boolean found, boolean debug);
 
@@ -109,12 +110,13 @@ public interface DaoMessage {
             " GROUP BY CASE WHEN message.thread IS NULL OR NOT :threading THEN message.id ELSE message.thread END" +
             " HAVING SUM(CASE WHEN folder.id = :folder THEN 1 ELSE 0 END) > 0" +
             " ORDER BY" +
-            " CASE WHEN 'sender' = :sort THEN message.sender ELSE '' END," +
             " CASE" +
-            "  WHEN 'unread' = :sort THEN " + unseen_folder + " > 0" +
-            "  WHEN 'starred' = :sort THEN COUNT(message.id) - " + unflagged_folder + " > 0" +
+            "  WHEN 'unread' = :sort THEN " + unseen_folder + " = 0" +
+            "  WHEN 'starred' = :sort THEN COUNT(message.id) - " + unflagged_folder + " = 0" +
+            "  WHEN 'sender' = :sort THEN LOWER(message.sender)" +
+            "  WHEN 'subject' = :sort THEN LOWER(message.subject)" +
             "  ELSE 0" +
-            " END DESC, message.received DESC")
+            " END, message.received DESC")
     @SuppressWarnings(RoomWarnings.CURSOR_MISMATCH)
     DataSource.Factory<Integer, TupleMessageEx> pagedFolder(long folder, boolean threading, String sort, boolean snoozed, boolean found, boolean debug);
 
diff --git a/app/src/main/java/eu/faircode/email/FragmentMessages.java b/app/src/main/java/eu/faircode/email/FragmentMessages.java
index 6d779e5faf..4822748e1a 100644
--- a/app/src/main/java/eu/faircode/email/FragmentMessages.java
+++ b/app/src/main/java/eu/faircode/email/FragmentMessages.java
@@ -1746,6 +1746,8 @@ public class FragmentMessages extends FragmentBase {
             menu.findItem(R.id.menu_sort_on_starred).setChecked(true);
         else if ("sender".equals(sort))
             menu.findItem(R.id.menu_sort_on_sender).setChecked(true);
+        else if ("subject".equals(sort))
+            menu.findItem(R.id.menu_sort_on_subject).setChecked(true);
 
         menu.findItem(R.id.menu_zoom).setVisible(!selection);
 
@@ -1787,6 +1789,11 @@ public class FragmentMessages extends FragmentBase {
                 onMenuSort("sender");
                 return true;
 
+            case R.id.menu_sort_on_subject:
+                item.setChecked(true);
+                onMenuSort("subject");
+                return true;
+
             case R.id.menu_zoom:
                 onMenuZoom();
                 return true;
diff --git a/app/src/main/res/menu/menu_messages.xml b/app/src/main/res/menu/menu_messages.xml
index 37c2560c16..7dd928a616 100644
--- a/app/src/main/res/menu/menu_messages.xml
+++ b/app/src/main/res/menu/menu_messages.xml
@@ -34,6 +34,9 @@
                 <item
                     android:id="@+id/menu_sort_on_sender"
                     android:title="@string/title_sort_on_sender" />
+                <item
+                    android:id="@+id/menu_sort_on_subject"
+                    android:title="@string/title_sort_on_subject" />
             </group>
         </menu>
     </item>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index a9a23d807b..1e00af485a 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -417,6 +417,7 @@
     <string name="title_sort_on_unread">Unread</string>
     <string name="title_sort_on_starred">Starred</string>
     <string name="title_sort_on_sender">Sender</string>
+    <string name="title_sort_on_subject">Subject</string>
 
     <string name="title_compact">Compact view</string>
     <string name="title_zoom">Text size</string>