diff --git a/eeschema/eeschema_config.cpp b/eeschema/eeschema_config.cpp
index 5e35bf7dcf..bdb1bcaa13 100644
--- a/eeschema/eeschema_config.cpp
+++ b/eeschema/eeschema_config.cpp
@@ -357,6 +357,7 @@ static const wxString RepeatStepXEntry =            "RepeatStepX";
 static const wxString RepeatStepYEntry =            "RepeatStepY";
 static const wxString RepeatLabelIncrementEntry =   "RepeatLabelIncrement";
 static const wxString ShowIllegalSymboLibDialog =   "ShowIllegalSymbolLibDialog";
+static const wxString showSheetFileNameCaseSensitivityDlg = "ShowSheetFileNameCaseSensitivityDlg";
 
 // Library editor wxConfig entry names.
 static const wxChar defaultLibWidthEntry[] =        wxT( "LibeditLibWidth" );
@@ -401,7 +402,9 @@ PARAM_CFG_ARRAY& SCH_EDIT_FRAME::GetConfigurationSettings()
                                                    -10, +10 ) );
     m_configSettings.push_back( new PARAM_CFG_BOOL( true, ShowIllegalSymboLibDialog,
                                                     &m_showIllegalSymbolLibDialog, true ) );
-
+    m_configSettings.push_back( new PARAM_CFG_BOOL( true, showSheetFileNameCaseSensitivityDlg,
+                                                    &m_showSheetFileNameCaseSensitivityDlg,
+                                                    true ) );
     return m_configSettings;
 }
 
@@ -547,6 +550,7 @@ void SCH_EDIT_FRAME::SaveSettings( wxConfigBase* aCfg )
     record.Replace( wxT("  "), wxT(" "), true );  // double space to single
 
     aCfg->Write( FieldNamesEntry, record );
+    aCfg->Write( showSheetFileNameCaseSensitivityDlg, m_showSheetFileNameCaseSensitivityDlg );
 }
 
 
diff --git a/eeschema/sch_edit_frame.cpp b/eeschema/sch_edit_frame.cpp
index 68ce0c8c34..1d4d05c4cf 100644
--- a/eeschema/sch_edit_frame.cpp
+++ b/eeschema/sch_edit_frame.cpp
@@ -387,6 +387,7 @@ SCH_EDIT_FRAME::SCH_EDIT_FRAME( KIWAY* aKiway, wxWindow* aParent ):
     m_undoItem = NULL;
     m_hasAutoSave = true;
     m_showIllegalSymbolLibDialog = true;
+    m_showSheetFileNameCaseSensitivityDlg = true;
     m_FrameSize = ConvertDialogToPixels( wxSize( 500, 350 ) );    // default in case of no prefs
     m_AboutTitle = "Eeschema";
 
diff --git a/eeschema/sch_edit_frame.h b/eeschema/sch_edit_frame.h
index 623440add9..9b6e575994 100644
--- a/eeschema/sch_edit_frame.h
+++ b/eeschema/sch_edit_frame.h
@@ -151,6 +151,7 @@ private:
     bool                    m_autoplaceAlign;     ///< align autoplaced fields to the grid
     bool                    m_footprintPreview;   ///< whether to show footprint previews
     bool                    m_showIllegalSymbolLibDialog;
+    bool                    m_showSheetFileNameCaseSensitivityDlg;
 
     /// An index to the last find item in the found items list #m_foundItems.
     int         m_foundItemIndex;
@@ -985,6 +986,19 @@ private:
      */
     bool importFile( const wxString& aFileName, int aFileType );
 
+    /**
+     * Check \a aSchematicFileName for a potential file name case sensitivity clashes.
+     *
+     * On platforms where file names are case sensitive, it is possible to schematic sheet
+     * file names that would cause issues on platforms where file name are case insensitive.
+     * File names foo.sch and Foo.sch are unique files on Linux and MacOS but on Windows
+     * this would result in a broken schematic.
+     *
+     * @param aSchematicFileName is the absolute path and file name of the file to test.
+     * @return true if the user accepts the potential file name clase risk.
+     */
+    bool allowCaseSensitiveFileNameClashes( const wxString& aSchematicFileName );
+
 public:
     /**
      * Command event handler to change a text type to another one.
diff --git a/eeschema/sch_screen.cpp b/eeschema/sch_screen.cpp
index be83a20463..4b44e3ffac 100644
--- a/eeschema/sch_screen.cpp
+++ b/eeschema/sch_screen.cpp
@@ -1619,6 +1619,29 @@ bool SCH_SCREENS::HasSchematic( const wxString& aSchematicFileName )
 }
 
 
+bool SCH_SCREENS::CanCauseCaseSensitivityIssue( const wxString& aSchematicFileName ) const
+{
+    wxFileName lhs;
+    wxFileName rhs = aSchematicFileName;
+
+    wxCHECK( rhs.IsAbsolute(), false );
+
+    for( const SCH_SCREEN* screen : m_screens )
+    {
+        lhs = screen->GetFileName();
+
+        if( lhs.GetPath() != rhs.GetPath() )
+            continue;
+
+        if( lhs.GetName().CmpNoCase( rhs.GetName() )
+          && lhs.GetName() != rhs.GetName() )
+            return true;
+    }
+
+    return false;
+}
+
+
 void SCH_SCREENS::BuildClientSheetPathList()
 {
     SCH_SHEET_LIST sheetList( g_RootSheet );
diff --git a/eeschema/sch_screen.h b/eeschema/sch_screen.h
index e065bd84ac..2647dfc809 100644
--- a/eeschema/sch_screen.h
+++ b/eeschema/sch_screen.h
@@ -639,6 +639,19 @@ public:
     void BuildClientSheetPathList();
 
 
+    /**
+     * Check \a aSchematicFileName for a potential file name case sensitivity issue.
+     *
+     * On platforms where file names are case sensitive, it is possible to schematic sheet
+     * file names that would cause issues on platforms where file name are case insensitive.
+     * File names foo.sch and Foo.sch are unique files on Linux and MacOS but on Windows
+     * this would result in a broken schematic.
+     *
+     * @param aSchematicFileName is the absolute path and file name of the file to test.
+     * @return true if \a aSchematicFileName would cause an issue.
+     */
+    bool CanCauseCaseSensitivityIssue( const wxString& aSchematicFileName ) const;
+
 private:
     void addScreenToList( SCH_SCREEN* aScreen );
     void buildScreenList( SCH_SHEET* aSheet);
diff --git a/eeschema/sch_sheet.cpp b/eeschema/sch_sheet.cpp
index f23a5bb93d..b180ff2db9 100644
--- a/eeschema/sch_sheet.cpp
+++ b/eeschema/sch_sheet.cpp
@@ -578,18 +578,36 @@ int SCH_SHEET::ComponentCount()
 
 bool SCH_SHEET::SearchHierarchy( const wxString& aFilename, SCH_SCREEN** aScreen )
 {
+    SCH_SHEET*  sheet = nullptr;
+    SCH_SCREEN* screen = nullptr;
+
     if( m_screen )
     {
+        // Only check the root sheet once and don't recurse.
+        if( !GetParent() )
+        {
+            sheet = this;
+            screen = m_screen;
+
+            if( screen && screen->GetFileName().Cmp( aFilename ) == 0 )
+            {
+                *aScreen = screen;
+                return true;
+            }
+        }
+
         EDA_ITEM* item = m_screen->GetDrawItems();
 
         while( item )
         {
             if( item->Type() == SCH_SHEET_T )
             {
-                SCH_SHEET* sheet = (SCH_SHEET*) item;
+                // Must use the screen's path (which is always absolute) rather than the
+                // sheet's (which could be relative).
+                sheet = static_cast< SCH_SHEET* >( item );
+                screen = sheet->m_screen;
 
-                if( sheet->m_screen
-                    && sheet->m_screen->GetFileName().CmpNoCase( aFilename ) == 0 )
+                if( screen && screen->GetFileName().Cmp( aFilename ) == 0 )
                 {
                     *aScreen = sheet->m_screen;
                     return true;
diff --git a/eeschema/sheet.cpp b/eeschema/sheet.cpp
index 5d41a9a837..2c104c4105 100644
--- a/eeschema/sheet.cpp
+++ b/eeschema/sheet.cpp
@@ -574,6 +574,9 @@ bool SCH_EDIT_FRAME::EditSheet( SCH_SHEET* aSheet, SCH_SHEET_PATH* aHierarchy,
 
     if( aSheet->GetScreen() == NULL )                 // New sheet.
     {
+        if( !allowCaseSensitiveFileNameClashes( newFilename ) )
+            return false;
+
         if( useScreen || loadFromFile )               // Load from existing file.
         {
             clearAnnotation = true;
@@ -605,6 +608,9 @@ bool SCH_EDIT_FRAME::EditSheet( SCH_SHEET* aSheet, SCH_SHEET_PATH* aHierarchy,
 
         isExistingSheet = true;
 
+        if( !allowCaseSensitiveFileNameClashes( newFilename ) )
+            return false;
+
         // Changing the filename of a sheet can modify the full hierarchy structure
         // and can be not always undoable.
         // So prepare messages for user notifications:
@@ -627,7 +633,7 @@ bool SCH_EDIT_FRAME::EditSheet( SCH_SHEET* aSheet, SCH_SHEET_PATH* aHierarchy,
         wxString oldFilename = aSheet->GetScreen()->GetFileName();
         oldFilename.Replace( wxT( "\\" ), wxT( "/" ) );
 
-        if( newFilename.CmpNoCase( oldFilename ) != 0 )
+        if( newFilename.Cmp( oldFilename ) != 0 )
         {
             // Sheet file name changes cannot be undone.
             isUndoable = false;
@@ -974,3 +980,37 @@ void SCH_EDIT_FRAME::MirrorSheet( SCH_SHEET* aSheet, bool aFromXaxis )
     GetCanvas()->GetView()->Update( aSheet );
     OnModify();
 }
+
+
+bool SCH_EDIT_FRAME::allowCaseSensitiveFileNameClashes( const wxString& aSchematicFileName )
+{
+    wxString msg;
+    SCH_SCREENS screens;
+    wxFileName fn = aSchematicFileName;
+
+    wxCHECK( fn.IsAbsolute(), false );
+
+    if( m_showSheetFileNameCaseSensitivityDlg
+      && screens.CanCauseCaseSensitivityIssue( aSchematicFileName ) )
+    {
+        msg.Printf( _( "The file name \"%s\" can cause issues with an existing file name\n"
+                       "already defined in the schematic on systems that support case\n"
+                       "insensitive file names.  This will cause issues if you copy this\n"
+                       "project to an operating system that supports case insensitive file\n"
+                       "names.\n\nDo you wish to continue?" ),
+                    fn.GetName() );
+
+        wxRichMessageDialog dlg( this, msg, _( "Warning" ),
+                                 wxYES_NO | wxNO_DEFAULT | wxICON_QUESTION );
+        dlg.ShowCheckBox( _( "Do not show this message again." ) );
+        dlg.SetYesNoLabels( wxMessageDialog::ButtonLabel( _( "Create New Sheet" ) ),
+                                wxMessageDialog::ButtonLabel( _( "Discard New Sheet" ) ) );
+
+        if( dlg.ShowModal() == wxID_NO )
+            return false;
+
+        m_showSheetFileNameCaseSensitivityDlg = !dlg.IsCheckBoxChecked();
+    }
+
+    return true;
+}