diff --git a/source/_UIAHandler.py b/source/_UIAHandler.py
index 76e0047d0a3..e377a88c045 100644
--- a/source/_UIAHandler.py
+++ b/source/_UIAHandler.py
@@ -58,7 +58,6 @@
 goodUIAWindowClassNames=[
 	# A WDAG (Windows Defender Application Guard) Window is always native UIA, even if it doesn't report as such.
 	'RAIL_WINDOW',
-	"EXCEL6",
 ]
 
 badUIAWindowClassNames=[
diff --git a/source/appModules/excel.py b/source/appModules/excel.py
index afe6cac130e..adac3378961 100644
--- a/source/appModules/excel.py
+++ b/source/appModules/excel.py
@@ -5,6 +5,7 @@
 # For more details see: https://www.gnu.org/licenses/gpl-2.0.html
 
 import time
+import config
 import eventHandler
 import api
 import UIAHandler
@@ -15,6 +16,8 @@
 from NVDAObjects.window.edit import UnidentifiedEdit
 from NVDAObjects.window import Window
 from NVDAObjects.window.excel import ExcelCell
+from NVDAObjects.IAccessible import IAccessible
+
 
 class Excel6(Window):
 	"""
@@ -43,6 +46,17 @@ def _get_focusRedirect(self):
 					self.focusRedirect=obj
 					return obj
 
+
+class Excel6_WhenUIAEnabled(IAccessible):
+	"""
+	#12303: When accessing Microsoft Excel via UI Automation
+	MSAA focus events on the old formula edit window should be completely ignored.
+	UI Automation will fire its own ones.
+	"""
+
+	shouldAllowIAccessibleFocusEvent = False
+
+
 class AppModule(appModuleHandler.AppModule):
 
 	def chooseNVDAObjectOverlayClasses(self, obj, clsList):
@@ -55,4 +69,14 @@ def chooseNVDAObjectOverlayClasses(self, obj, clsList):
 				pass
 			clsList.insert(0, DisplayModelEditableText)
 		if windowClass=="EXCEL6":
-			clsList.insert(0,Excel6)
+			if config.conf["UIA"]["useInMSExcelWhenAvailable"]:
+				# #12303: When accessing Microsoft Excel via UI Automation
+				# MSAA focus events on the old formula edit window should be completely ignored.
+				# UI Automation will fire its own ones.
+				clsList.insert(0, Excel6_WhenUIAEnabled)
+			else:
+				# #12303: The old Formula Edit window in recent versions of Excel
+				# may not be accessible with display models as GDI is no longer used.
+				# However, UI Automation does expose an accessible edit control within the active cell,
+				# So use a class that will redirect focus to that.
+				clsList.insert(0, Excel6)