diff --git a/src/debugger/gui/DebuggerDialog.cxx b/src/debugger/gui/DebuggerDialog.cxx
index c1a183f32..f7772e83a 100644
--- a/src/debugger/gui/DebuggerDialog.cxx
+++ b/src/debugger/gui/DebuggerDialog.cxx
@@ -157,9 +157,9 @@ void DebuggerDialog::showFatalMessage(const string& msg)
 
   delete myFatalError;
   myFatalError =
-    new MessageBox(this, instance().consoleFont(), msg,
-                   r.width(), r.height(), kDDExitFatalCmd,
-                   "Exit ROM", "Continue");
+    new GUI::MessageBox(this, instance().consoleFont(), msg,
+                        r.width(), r.height(), kDDExitFatalCmd,
+                        "Exit ROM", "Continue");
   myFatalError->show();
 }
 
diff --git a/src/debugger/gui/DebuggerDialog.hxx b/src/debugger/gui/DebuggerDialog.hxx
index d0a029a8d..c3a536a98 100644
--- a/src/debugger/gui/DebuggerDialog.hxx
+++ b/src/debugger/gui/DebuggerDialog.hxx
@@ -36,9 +36,9 @@ class EditTextWidget;
 class TiaInfoWidget;
 class TiaOutputWidget;
 class TiaZoomWidget;
-class MessageBox;
 
 #include "Dialog.hxx"
+#include "MessageBox.hxx"
 
 class DebuggerDialog : public Dialog
 {
@@ -83,7 +83,7 @@ class DebuggerDialog : public Dialog
     RomWidget*       myRom;
     EditTextWidget*  myMessageBox;
     ButtonWidget*    myRewindButton;
-    MessageBox*      myFatalError;
+    GUI::MessageBox* myFatalError;
 
   private:
     void addTiaArea();
diff --git a/src/gui/LauncherDialog.cxx b/src/gui/LauncherDialog.cxx
index 4589278b5..49fbb1cb2 100644
--- a/src/gui/LauncherDialog.cxx
+++ b/src/gui/LauncherDialog.cxx
@@ -251,8 +251,8 @@ void LauncherDialog::loadConfig()
       msg.push_back("");
       msg.push_back("Click 'OK' to select a default ROM directory,");
       msg.push_back("or 'Cancel' to browse the filesystem manually.");
-      myFirstRunMsg = new MessageBox(this, instance().font(), msg,
-                                     _w, _h, kFirstRunMsgChosenCmd);
+      myFirstRunMsg = new GUI::MessageBox(this, instance().font(), msg,
+                                          _w, _h, kFirstRunMsgChosenCmd);
     }
     myFirstRunMsg->show();
   }
diff --git a/src/gui/LauncherDialog.hxx b/src/gui/LauncherDialog.hxx
index 064c103a6..90a1d35f1 100644
--- a/src/gui/LauncherDialog.hxx
+++ b/src/gui/LauncherDialog.hxx
@@ -34,7 +34,6 @@ class BrowserDialog;
 class OptionsDialog;
 class GlobalPropsDialog;
 class LauncherFilterDialog;
-class MessageBox;
 class OSystem;
 class Properties;
 class EditTextWidget;
@@ -46,6 +45,7 @@ class StringListWidget;
 #include "FSNode.hxx"
 #include "StringList.hxx"
 #include "Stack.hxx"
+#include "MessageBox.hxx"
 
 // These must be accessible from dialogs created by this class
 enum {
@@ -118,8 +118,8 @@ class LauncherDialog : public Dialog
     GlobalPropsDialog*    myGlobalProps;
     LauncherFilterDialog* myFilters;
 
-    MessageBox*    myFirstRunMsg;
-    BrowserDialog* myRomDir;
+    GUI::MessageBox* myFirstRunMsg;
+    BrowserDialog*   myRomDir;
 
     int mySelectedItem;
     int myRomInfoSize;
diff --git a/src/gui/MessageBox.cxx b/src/gui/MessageBox.cxx
index 6d3aed290..98df7ecd3 100644
--- a/src/gui/MessageBox.cxx
+++ b/src/gui/MessageBox.cxx
@@ -25,6 +25,8 @@
 
 #include "MessageBox.hxx"
 
+namespace GUI {
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 MessageBox::MessageBox(GuiObject* boss, const GUI::Font& font,
                        const StringList& text, int max_w, int max_h, int cmd,
@@ -107,3 +109,5 @@ void MessageBox::handleCommand(CommandSender* sender, int cmd, int data, int id)
       break;
   }
 }
+
+}  // namespace GUI
diff --git a/src/gui/MessageBox.hxx b/src/gui/MessageBox.hxx
index c4a078728..89f4759ae 100644
--- a/src/gui/MessageBox.hxx
+++ b/src/gui/MessageBox.hxx
@@ -27,6 +27,8 @@ class StaticTextWidget;
 #include "Command.hxx"
 #include "DialogContainer.hxx"
 
+namespace GUI {
+
 /**
  * Show a simple message box containing the given text, with buttons 
  * prompting the user to accept or reject.  If the user selects 'OK',
@@ -54,4 +56,6 @@ class MessageBox : public Dialog, public CommandSender
     int myCmd;
 };
 
+}  // namespace GUI
+
 #endif
diff --git a/src/gui/Rect.hxx b/src/gui/Rect.hxx
index 05dd63df7..7b4ce3771 100644
--- a/src/gui/Rect.hxx
+++ b/src/gui/Rect.hxx
@@ -166,6 +166,6 @@ struct Rect
   }
 };
 
-}  // End of namespace Common
+}  // End of namespace GUI
 
 #endif
diff --git a/src/gui/RomAuditDialog.cxx b/src/gui/RomAuditDialog.cxx
index b9c32f224..397db3abe 100644
--- a/src/gui/RomAuditDialog.cxx
+++ b/src/gui/RomAuditDialog.cxx
@@ -190,8 +190,9 @@ void RomAuditDialog::handleCommand(CommandSender* sender, int cmd,
         msg.push_back("If you're sure you want to proceed with the");
         msg.push_back("audit, click 'OK', otherwise click 'Cancel'.");
         myConfirmMsg =
-          new MessageBox(this, instance().font(), msg, myMaxWidth, myMaxHeight,
-                         kConfirmAuditCmd);
+          new GUI::MessageBox(this, instance().font(), msg,
+                              myMaxWidth, myMaxHeight,
+                              kConfirmAuditCmd);
       }
       myConfirmMsg->show();
       break;
diff --git a/src/gui/RomAuditDialog.hxx b/src/gui/RomAuditDialog.hxx
index 942f161a7..6ea68b3bb 100644
--- a/src/gui/RomAuditDialog.hxx
+++ b/src/gui/RomAuditDialog.hxx
@@ -29,11 +29,11 @@ class DialogContainer;
 class BrowserDialog;
 class EditTextWidget;
 class StaticTextWidget;
-class MessageBox;
 
 #include "Dialog.hxx"
 #include "Command.hxx"
 #include "FSNode.hxx"
+#include "MessageBox.hxx"
 
 class RomAuditDialog : public Dialog
 {
@@ -68,7 +68,7 @@ class RomAuditDialog : public Dialog
     BrowserDialog* myBrowser;
 
     // Show a message about the dangers of using this function
-    MessageBox* myConfirmMsg;
+    GUI::MessageBox* myConfirmMsg;
 
     // Maximum width and height for this dialog
     int myMaxWidth, myMaxHeight;