diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index 7c1f20b6d7..c2c010ded6 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -143,6 +143,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
     private boolean subject_italic;
     private int zoom;
     private String sort;
+    private boolean duplicates;
     private boolean suitable;
     private IProperties properties;
 
@@ -462,6 +463,9 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
             setDisplacement(0);
             pbLoading.setVisibility(View.GONE);
 
+            if (viewType == ViewType.THREAD)
+                view.setVisibility(duplicates || !message.duplicate ? View.VISIBLE : View.GONE);
+
             // Text size
             if (textSize != 0) {
                 tvDay.setTextSize(TypedValue.COMPLEX_UNIT_PX, textSize);
@@ -2923,7 +2927,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
     }
 
     AdapterMessage(Context context, LifecycleOwner owner,
-                   ViewType viewType, boolean compact, int zoom, String sort, IProperties properties) {
+                   ViewType viewType, boolean compact, int zoom, String sort, boolean duplicates, IProperties properties) {
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
 
         this.context = context;
@@ -2935,6 +2939,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
         this.subject_italic = prefs.getBoolean("subject_italic", true);
         this.zoom = zoom;
         this.sort = sort;
+        this.duplicates = duplicates;
         this.suitable = Helper.getNetworkState(context).isSuitable();
         this.properties = properties;
 
@@ -3016,6 +3021,13 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
         }
     }
 
+    void setDuplicates(boolean duplicates) {
+        if (this.duplicates != duplicates) {
+            this.duplicates = duplicates;
+            notifyDataSetChanged();
+        }
+    }
+
     void checkInternet() {
         boolean suitable = Helper.getNetworkState(context).isSuitable();
         if (this.suitable != suitable) {
diff --git a/app/src/main/java/eu/faircode/email/FragmentMessages.java b/app/src/main/java/eu/faircode/email/FragmentMessages.java
index 833d5fd17a..887dd420b6 100644
--- a/app/src/main/java/eu/faircode/email/FragmentMessages.java
+++ b/app/src/main/java/eu/faircode/email/FragmentMessages.java
@@ -312,10 +312,11 @@ public class FragmentMessages extends FragmentBase {
         boolean compact = prefs.getBoolean("compact", false);
         int zoom = prefs.getInt("zoom", compact ? 0 : 1);
         String sort = prefs.getString("sort", "time");
+        boolean duplicates = prefs.getBoolean("duplicates", true);
 
         adapter = new AdapterMessage(
                 getContext(), getViewLifecycleOwner(),
-                viewType, compact, zoom, sort, iProperties);
+                viewType, compact, zoom, sort, duplicates, iProperties);
 
         rvMessage.setAdapter(adapter);
 
@@ -1835,6 +1836,9 @@ public class FragmentMessages extends FragmentBase {
                 (viewType == AdapterMessage.ViewType.UNIFIED || viewType == AdapterMessage.ViewType.FOLDER));
         menu.findItem(R.id.menu_snoozed).setChecked(prefs.getBoolean("snoozed", false));
 
+        menu.findItem(R.id.menu_duplicates).setVisible(viewType == AdapterMessage.ViewType.THREAD);
+        menu.findItem(R.id.menu_duplicates).setChecked(prefs.getBoolean("duplicates", true));
+
         super.onPrepareOptionsMenu(menu);
     }
 
@@ -1883,6 +1887,10 @@ public class FragmentMessages extends FragmentBase {
                 onMenuSnoozed();
                 return true;
 
+            case R.id.menu_duplicates:
+                onMenuDuplicates();
+                return true;
+
             default:
                 return super.onOptionsItemSelected(item);
         }
@@ -1939,6 +1947,13 @@ public class FragmentMessages extends FragmentBase {
         loadMessages();
     }
 
+    private void onMenuDuplicates() {
+        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
+        boolean duplicates = prefs.getBoolean("duplicates", true);
+        prefs.edit().putBoolean("duplicates", !duplicates).apply();
+        adapter.setDuplicates(!duplicates);
+    }
+
     private void loadMessages() {
         if (viewType == AdapterMessage.ViewType.THREAD && autonext) {
             ViewModelMessages model = ViewModelProviders.of(getActivity()).get(ViewModelMessages.class);
diff --git a/app/src/main/res/menu/menu_messages.xml b/app/src/main/res/menu/menu_messages.xml
index 7dd928a616..91ccab7566 100644
--- a/app/src/main/res/menu/menu_messages.xml
+++ b/app/src/main/res/menu/menu_messages.xml
@@ -58,4 +58,10 @@
         android:checkable="true"
         android:title="@string/title_snoozed"
         app:showAsAction="never" />
+
+    <item
+        android:id="@+id/menu_duplicates"
+        android:checkable="true"
+        android:title="@string/title_duplicates"
+        app:showAsAction="never" />
 </menu>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 77ef73e956..fb6ba1461c 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -433,6 +433,7 @@
     <string name="title_address_unsent">Unsent:</string>
     <string name="title_address_invalid">Invalid:</string>
     <string name="title_snoozed">Snoozed</string>
+    <string name="title_duplicates">Show duplicates</string>
 
     <string name="title_previous">Previous</string>
     <string name="title_next">Next</string>