diff --git a/src/Commands/MergeTool.cs b/src/Commands/MergeTool.cs
index d3478d59..276c078b 100644
--- a/src/Commands/MergeTool.cs
+++ b/src/Commands/MergeTool.cs
@@ -13,9 +13,12 @@ namespace SourceGit.Commands
             cmd.Context = repo;
             cmd.RaiseError = true;
 
+            // NOTE: If no <file> names are specified, 'git mergetool' will run the merge tool program on every file with merge conflicts.
+            var file_arg = string.IsNullOrEmpty(file) ? "" : $"\"{file}\"";
+
             if (toolType == 0)
             {
-                cmd.Args = $"mergetool \"{file}\"";
+                cmd.Args = $"mergetool {file_arg}";
                 return cmd.Exec();
             }
 
@@ -32,7 +35,7 @@ namespace SourceGit.Commands
                 return false;
             }
 
-            cmd.Args = $"-c mergetool.sourcegit.cmd=\"\\\"{toolPath}\\\" {supported.Cmd}\" -c mergetool.writeToTemp=true -c mergetool.keepBackup=false -c mergetool.trustExitCode=true mergetool --tool=sourcegit \"{file}\"";
+            cmd.Args = $"-c mergetool.sourcegit.cmd=\"\\\"{toolPath}\\\" {supported.Cmd}\" -c mergetool.writeToTemp=true -c mergetool.keepBackup=false -c mergetool.trustExitCode=true mergetool --tool=sourcegit {file_arg}";
             return cmd.Exec();
         }
 
diff --git a/src/Resources/Locales/en_US.axaml b/src/Resources/Locales/en_US.axaml
index 4694eb3a..9676d371 100644
--- a/src/Resources/Locales/en_US.axaml
+++ b/src/Resources/Locales/en_US.axaml
@@ -727,6 +727,7 @@
   <x:String x:Key="Text.WorkingCopy.ConfirmCommitWithFilter">You have staged {0} file(s) but only {1} file(s) displayed ({2} files are filtered out). Do you want to continue?</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts" xml:space="preserve">CONFLICTS DETECTED</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.OpenExternalMergeTool" xml:space="preserve">OPEN EXTERNAL MERGETOOL</x:String>
+  <x:String x:Key="Text.WorkingCopy.Conflicts.OpenExternalMergeToolAllConflicts" xml:space="preserve">OPEN ALL CONFLICTS IN EXTERNAL MERGETOOL</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.Resolved" xml:space="preserve">FILE CONFLICTS ARE RESOLVED</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.UseMine" xml:space="preserve">USE MINE</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.UseTheirs" xml:space="preserve">USE THEIRS</x:String>
diff --git a/src/ViewModels/WorkingCopy.cs b/src/ViewModels/WorkingCopy.cs
index 83813f39..dea8acea 100644
--- a/src/ViewModels/WorkingCopy.cs
+++ b/src/ViewModels/WorkingCopy.cs
@@ -314,6 +314,12 @@ namespace SourceGit.ViewModels
             });
         }
 
+        public void OpenExternalMergeToolAllConflicts()
+        {
+            // No <file> arg, mergetool runs on all files with merge conflicts!
+            UseExternalMergeTool(null);
+        }
+
         public void OpenAssumeUnchanged()
         {
             App.OpenDialog(new Views.AssumeUnchangedManager()
@@ -448,7 +454,8 @@ namespace SourceGit.ViewModels
         {
             var toolType = Preferences.Instance.ExternalMergeToolType;
             var toolPath = Preferences.Instance.ExternalMergeToolPath;
-            await Task.Run(() => Commands.MergeTool.OpenForMerge(_repo.FullPath, toolType, toolPath, change.Path));
+            var file = change?.Path; // NOTE: With no <file> arg, mergetool runs on on every file with merge conflicts!
+            await Task.Run(() => Commands.MergeTool.OpenForMerge(_repo.FullPath, toolType, toolPath, file));
         }
 
         public void ContinueMerge()
diff --git a/src/Views/WorkingCopy.axaml b/src/Views/WorkingCopy.axaml
index 4ca854fa..7d471142 100644
--- a/src/Views/WorkingCopy.axaml
+++ b/src/Views/WorkingCopy.axaml
@@ -61,13 +61,22 @@
       <Grid Grid.Row="1" RowDefinitions="28,*">
         <!-- Unstaged Toolbar -->
         <Border Grid.Row="0" BorderThickness="0,0,0,1" BorderBrush="{DynamicResource Brush.Border0}">
-          <Grid ColumnDefinitions="Auto,Auto,Auto,Auto,*,Auto,Auto,Auto,Auto,Auto">
+          <Grid ColumnDefinitions="Auto,Auto,Auto,Auto,*,Auto,Auto,Auto,Auto,Auto,Auto">
             <Path Grid.Column="0" Margin="8,0,0,0" Width="14" Height="14" Fill="{DynamicResource Brush.FG2}" Data="{StaticResource Icons.Changes}"/>
             <TextBlock Grid.Column="1" Text="{DynamicResource Text.WorkingCopy.Unstaged}" Foreground="{DynamicResource Brush.FG2}" FontWeight="Bold" Margin="4,0,0,0"/>
             <TextBlock Grid.Column="2" FontWeight="Bold" Foreground="{DynamicResource Brush.FG2}" Text="{Binding Unstaged, Converter={x:Static c:ListConverters.ToCount}}"/>
             <v:LoadingIcon Grid.Column="3" Width="14" Height="14" Margin="8,0,0,0" IsVisible="{Binding IsStaging}"/>
 
             <Button Grid.Column="5"
+                    Classes="icon_button"
+                    Width="26" Height="14"
+                    Padding="0"
+                    IsVisible="{Binding HasUnsolvedConflicts}"
+                    ToolTip.Tip="{DynamicResource Text.WorkingCopy.Conflicts.OpenExternalMergeToolAllConflicts}"
+                    Command="{Binding OpenExternalMergeToolAllConflicts}">
+              <Path Width="14" Height="14" Data="{StaticResource Icons.Conflict}"/>
+            </Button>
+            <Button Grid.Column="6"
                     Classes="icon_button"
                     Width="26" Height="14"
                     Padding="0"
@@ -75,12 +84,12 @@
                     Command="{Binding OpenAssumeUnchanged}">
               <Path Width="14" Height="14" Data="{StaticResource Icons.File.Ignore}"/>
             </Button>
-            <ToggleButton Grid.Column="6"
+            <ToggleButton Grid.Column="7"
                           Classes="toggle_untracked"
                           Width="26" Height="14"
                           ToolTip.Tip="{DynamicResource Text.WorkingCopy.IncludeUntracked}"
                           IsChecked="{Binding IncludeUntracked, Mode=TwoWay}"/>
-            <Button Grid.Column="7"
+            <Button Grid.Column="8"
                     Classes="icon_button"
                     Width="26" Height="14"
                     Padding="0"
@@ -93,7 +102,7 @@
               </ToolTip.Tip>
               <Path Width="14" Height="14" Margin="0,6,0,0" Data="{StaticResource Icons.Down}"/>
             </Button>
-            <Button Grid.Column="8"
+            <Button Grid.Column="9"
                     Classes="icon_button"
                     Width="26" Height="14"
                     Padding="0"
@@ -101,7 +110,7 @@
                     Command="{Binding StageAll}">
               <Path Width="14" Height="14" Data="{StaticResource Icons.DoubleDown}"/>
             </Button>
-            <v:ChangeViewModeSwitcher Grid.Column="9"
+            <v:ChangeViewModeSwitcher Grid.Column="10"
                                       Width="26" Height="14"
                                       Margin="0,1,0,0"
                                       ViewMode="{Binding Source={x:Static vm:Preferences.Instance}, Path=UnstagedChangeViewMode, Mode=TwoWay}"/>