diff --git a/lib/buildPlugin.nix b/lib/buildPlugin.nix
index f0b50c2..370802f 100644
--- a/lib/buildPlugin.nix
+++ b/lib/buildPlugin.nix
@@ -198,6 +198,13 @@ in {
     libExt = gen.libExt;
 
   in pkgs.stdenv.mkDerivation (commonArgs // {
+    # Required wherever the Qt wrapper hooks are absent (Windows -- see
+    # common.nix): qtbase's setup hook hard-errors in qtPreHook with
+    # "depends on qtbase, but no wrapping behavior was specified" unless one of
+    # the two is present. Harmless elsewhere: these are plugins, not
+    # applications, so there is nothing to wrap.
+    dontWrapQtApps = true;
+
     pname = "${commonArgs.pname}-lib";
 
     inherit src;
@@ -366,6 +373,13 @@ in {
     };
 
   in pkgs.stdenv.mkDerivation (commonArgs // {
+    # Required wherever the Qt wrapper hooks are absent (Windows -- see
+    # common.nix): qtbase's setup hook hard-errors in qtPreHook with
+    # "depends on qtbase, but no wrapping behavior was specified" unless one of
+    # the two is present. Harmless elsewhere: these are plugins, not
+    # applications, so there is nothing to wrap.
+    dontWrapQtApps = true;
+
     pname = "${commonArgs.pname}-generated";
 
     inherit src;
diff --git a/lib/common.nix b/lib/common.nix
index 5b38ecf..b014a8a 100644
--- a/lib/common.nix
+++ b/lib/common.nix
@@ -5,9 +5,13 @@
 # and it's passed in by the caller.
 { lib }:
 
-{
-  # Supported target systems
-  systems = [ "aarch64-darwin" "x86_64-darwin" "aarch64-linux" "x86_64-linux" ];
+# `rec` so getPluginFilename can reuse getLibExtension instead of repeating the
+# platform branch -- the duplication is exactly what let them disagree about
+# Windows.
+rec {
+  # Supported target systems. "x86_64-windows" is a pseudo-system: a cross
+  # derivation's `system` attribute is its BUILD platform.
+  systems = [ "aarch64-darwin" "x86_64-darwin" "aarch64-linux" "x86_64-linux" "x86_64-windows" ];
 
   # Determine library extension based on platform
   getLibExtension = pkgs:
@@ -15,16 +19,26 @@
     else if pkgs.stdenv.hostPlatform.isWindows then "dll"
     else "so";
 
-  # Get the plugin filename for a module
+  # Get the plugin filename for a module.
+  #
+  # Reuses getLibExtension rather than repeating the branch: this used to have
+  # its own darwin/else test and returned ".so" on Windows, disagreeing with
+  # getLibExtension two lines above, which already answered "dll".
   getPluginFilename = pkgs: name:
-    "${name}_plugin.${if pkgs.stdenv.hostPlatform.isDarwin then "dylib" else "so"}";
+    "${name}_plugin.${getLibExtension pkgs}";
 
   # Qt-specific native build inputs
   commonNativeBuildInputs = pkgs: [
     pkgs.cmake
     pkgs.ninja
     pkgs.pkg-config
-    pkgs.qt6.wrapQtAppsNoGuiHook
+    # Mandatory guard, not an optimisation: wrapQtAppsNoGuiHook does not even
+    # EVALUATE for a mingw host, and would be inert anyway -- wrap-qt-apps-hook
+    # skips anything that is not ELF or Mach-O, so a PE is never wrapped.
+    # qtbase's own setup hook then hard-errors in qtPreHook unless
+    # dontWrapQtApps is set, which is why both halves are needed.
+  ] ++ pkgs.lib.optional (!pkgs.stdenv.hostPlatform.isWindows)
+    pkgs.qt6.wrapQtAppsNoGuiHook ++ [
   ];
 
   # Qt-specific build inputs
diff --git a/lib/default.nix b/lib/default.nix
index 081f7e2..6ab40fb 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -51,7 +51,7 @@ in {
       } // extraEnv;
       meta = with lib; {
         description = config.description;
-        platforms = platforms.unix;
+        platforms = platforms.unix ++ platforms.windows;
       };
     };
   in mkBuildPlugin.build {
@@ -93,7 +93,7 @@ in {
       } // extraEnv;
       meta = with lib; {
         description = config.description;
-        platforms = platforms.unix;
+        platforms = platforms.unix ++ platforms.windows;
       };
     };
   in mkBuildPlugin.generate {
@@ -122,7 +122,7 @@ in {
       version = config.version;
       meta = with lib; {
         description = config.description;
-        platforms = platforms.unix;
+        platforms = platforms.unix ++ platforms.windows;
       };
     };
   in mkBuildHeaders.build {