diff --git a/pkgs/applications/audio/musescore/default.nix b/pkgs/applications/audio/musescore/default.nix
index 66275bdac495..ff57eb3f4799 100644
--- a/pkgs/applications/audio/musescore/default.nix
+++ b/pkgs/applications/audio/musescore/default.nix
@@ -2,6 +2,7 @@
   stdenv,
   lib,
   fetchFromGitHub,
+  fetchpatch,
   cmake,
   wrapGAppsHook3,
   wrapQtAppsHook,
@@ -44,6 +45,16 @@ stdenv.mkDerivation (finalAttrs: {
     sha256 = "sha256-ha3rBILekycHiPdcaPNsbvlF289NzFs9srP3unOuJRg=";
   };
 
+  # Backport + additional patch to fix build on Qt 6.9
+  # FIXME: remove when no longer required
+  patches = [
+    (fetchpatch {
+      url = "https://github.com/musescore/MuseScore/commit/05056ed19520060c3912a09a3adfa0927057f956.patch";
+      hash = "sha256-50Hytuu2lQRbAI2JEwlKeMUmJxTUtfqgwru6U760hAY=";
+    })
+    ./qt-6.9.patch
+  ];
+
   cmakeFlags = [
     "-DMUSE_APP_BUILD_MODE=release"
     # Disable the build and usage of the `/bin/crashpad_handler` utility - it's
diff --git a/pkgs/applications/audio/musescore/qt-6.9.patch b/pkgs/applications/audio/musescore/qt-6.9.patch
new file mode 100644
index 000000000000..d4cc3cacb556
--- /dev/null
+++ b/pkgs/applications/audio/musescore/qt-6.9.patch
@@ -0,0 +1,13 @@
+diff --git a/src/palette/view/widgets/specialcharactersdialog.cpp b/src/palette/view/widgets/specialcharactersdialog.cpp
+index 2fe07bdb8f..dfcae1ded7 100644
+--- a/src/palette/view/widgets/specialcharactersdialog.cpp
++++ b/src/palette/view/widgets/specialcharactersdialog.cpp
+@@ -712,7 +712,7 @@ void SpecialCharactersDialog::populateUnicode()
+         std::shared_ptr<FSymbol> fs = std::make_shared<FSymbol>(gpaletteScore->dummy());
+         fs->setCode(code);
+         fs->setFont(m_font);
+-        m_pUnicode->appendElement(fs, QString("0x%1").arg(code, 5, 16, QLatin1Char('0')));
++        m_pUnicode->appendElement(fs, QString("0x%1").arg((uint32_t)code, 5, 16, QLatin1Char('0')));
+     }
+ }
+