diff --git a/modules/i18n/input-method/fcitx5.nix b/modules/i18n/input-method/fcitx5.nix
index 1787a2366..3599fd2dc 100644
--- a/modules/i18n/input-method/fcitx5.nix
+++ b/modules/i18n/input-method/fcitx5.nix
@@ -29,7 +29,7 @@ in {
       QT_IM_MODULE = "fcitx";
       XMODIFIERS = "@im=fcitx";
       QT_PLUGIN_PATH =
-        "${fcitx5Package}/${pkgs.qt6.qtbase.qtPluginPrefix}:\${QT_PLUGIN_PATH}";
+        "$QT_PLUGIN_PATH\${QT_PLUGIN_PATH:+:}${fcitx5Package}/${pkgs.qt6.qtbase.qtPluginPrefix}";
     };
 
     systemd.user.services.fcitx5-daemon = {
diff --git a/modules/misc/qt.nix b/modules/misc/qt.nix
index d11976831..495841ea4 100644
--- a/modules/misc/qt.nix
+++ b/modules/misc/qt.nix
@@ -1,25 +1,37 @@
 { config, lib, pkgs, ... }:
 
-with lib;
-
 let
-
   cfg = config.qt;
 
+  # Map platform names to their packages.
+  platformPackages = with pkgs; {
+    gnome = [ qgnomeplatform qgnomeplatform-qt6 ];
+    gtk = [ libsForQt5.qtstyleplugins qt6Packages.qt6gtk2 ];
+    kde = [ libsForQt5.plasma-integration libsForQt5.systemsettings ];
+    lxqt = [ lxqt.lxqt-qtplugin lxqt.lxqt-config ];
+    qtct = [ libsForQt5.qt5ct qt6Packages.qt6ct ];
+  };
+
+  # Maps style names to their QT_QPA_PLATFORMTHEME, if necessary.
+  styleNames = {
+    gtk = "gtk2";
+    qtct = "qt5ct";
+  };
+
   # Maps known lowercase style names to style packages. Non-exhaustive.
   stylePackages = with pkgs; {
     bb10bright = libsForQt5.qtstyleplugins;
     bb10dark = libsForQt5.qtstyleplugins;
     cleanlooks = libsForQt5.qtstyleplugins;
-    gtk2 = libsForQt5.qtstyleplugins;
+    gtk2 = [ libsForQt5.qtstyleplugins qt6Packages.qt6gtk2 ];
     motif = libsForQt5.qtstyleplugins;
     cde = libsForQt5.qtstyleplugins;
     plastique = libsForQt5.qtstyleplugins;
 
-    adwaita = adwaita-qt;
-    adwaita-dark = adwaita-qt;
-    adwaita-highcontrast = adwaita-qt;
-    adwaita-highcontrastinverse = adwaita-qt;
+    adwaita = [ adwaita-qt adwaita-qt6 ];
+    adwaita-dark = [ adwaita-qt adwaita-qt6 ];
+    adwaita-highcontrast = [ adwaita-qt adwaita-qt6 ];
+    adwaita-highcontrastinverse = [ adwaita-qt adwaita-qt6 ];
 
     breeze = libsForQt5.breeze-qt5;
 
@@ -28,29 +40,37 @@ let
   };
 
 in {
-  meta.maintainers = with maintainers; [ rycee thiagokokada ];
+  meta.maintainers = with lib.maintainers; [ rycee thiagokokada ];
 
   imports = [
-    (mkChangedOptionModule [ "qt" "useGtkTheme" ] [ "qt" "platformTheme" ]
+    (lib.mkChangedOptionModule [ "qt" "useGtkTheme" ] [ "qt" "platformTheme" ]
       (config:
-        if getAttrFromPath [ "qt" "useGtkTheme" ] config then "gtk" else null))
+        if lib.getAttrFromPath [ "qt" "useGtkTheme" ] config then
+          "gtk"
+        else
+          null))
   ];
 
   options = {
     qt = {
-      enable = mkEnableOption "Qt 4, 5 and 6 configuration";
+      enable = lib.mkEnableOption "Qt 5 and 6 configuration";
 
-      platformTheme = mkOption {
-        type = types.nullOr (types.enum [ "gtk" "gnome" "qtct" "kde" ]);
+      platformTheme = lib.mkOption {
+        type = with lib.types;
+          nullOr (enum [ "gtk" "gtk3" "gnome" "lxqt" "qtct" "kde" ]);
         default = null;
         example = "gnome";
         relatedPackages = [
           "qgnomeplatform"
-          [ "libsForQt5" "qtstyleplugins" ]
-          [ "libsForQt5" "qt5ct" ]
-          [ "qt6Packages" "qt6ct" ]
+          "qgnomeplatform-qt6"
           [ "libsForQt5" "plasma-integration" ]
+          [ "libsForQt5" "qt5ct" ]
+          [ "libsForQt5" "qtstyleplugins" ]
           [ "libsForQt5" "systemsettings" ]
+          [ "lxqt" "lxqt-config" ]
+          [ "lxqt" "lxqt-qtplugin" ]
+          [ "qt6Packages" "qt6ct" ]
+          [ "qt6Packages" "qt6gtk2" ]
         ];
         description = ''
           Platform theme to use for Qt applications.
@@ -61,10 +81,19 @@ in {
           : Use GTK theme with
             [`qtstyleplugins`](https://github.com/qt/qtstyleplugins)
 
+          `gtk3`
+          : Use [GTK3 integration](https://github.com/qt/qtbase/tree/dev/src/plugins/platformthemes/gtk3)
+            for file picker dialogs, font and theme configuration
+
           `gnome`
           : Use GNOME theme with
             [`qgnomeplatform`](https://github.com/FedoraQt/QGnomePlatform)
 
+          `lxqt`
+          : Use LXQt theme style set using the
+            [`lxqt-config-appearance`](https://github.com/lxqt/lxqt-config)
+            application
+
           `qtct`
           : Use Qt style set using
             [`qt5ct`](https://github.com/desktop-app/qt5ct)
@@ -77,15 +106,17 @@ in {
       };
 
       style = {
-        name = mkOption {
-          type = types.nullOr types.str;
+        name = lib.mkOption {
+          type = with lib.types; nullOr str;
           default = null;
           example = "adwaita-dark";
           relatedPackages = [
             "adwaita-qt"
+            "adwaita-qt6"
             [ "libsForQt5" "breeze-qt5" ]
-            [ "libsForQt5" "qtstyleplugins" ]
             [ "libsForQt5" "qtstyleplugin-kvantum" ]
+            [ "libsForQt5" "qtstyleplugins" ]
+            [ "qt6Packages" "qt6gtk2" ]
             [ "qt6Packages" "qtstyleplugin-kvantum" ]
           ];
           description = ''
@@ -111,10 +142,10 @@ in {
           '';
         };
 
-        package = mkOption {
-          type = with types; nullOr (either package (listOf package));
+        package = lib.mkOption {
+          type = with lib.types; nullOr (either package (listOf package));
           default = null;
-          example = literalExpression "pkgs.adwaita-qt";
+          example = lib.literalExpression "pkgs.adwaita-qt";
           description = ''
             Theme package to be used in Qt5/Qt6 applications.
             Auto-detected from {option}`qt.style.name` if possible.
@@ -127,17 +158,26 @@ in {
   config = let
 
     # Necessary because home.sessionVariables doesn't support mkIf
-    envVars = filterAttrs (n: v: v != null) {
-      QT_QPA_PLATFORMTHEME = if cfg.platformTheme == "gtk" then
-        "gtk2"
-      else if cfg.platformTheme == "qtct" then
-        "qt5ct"
-      else
-        cfg.platformTheme;
+    envVars = lib.filterAttrs (n: v: v != null) {
+      QT_QPA_PLATFORMTHEME =
+        styleNames.${cfg.platformTheme} or cfg.platformTheme;
       QT_STYLE_OVERRIDE = cfg.style.name;
     };
 
-  in mkIf (cfg.enable && cfg.platformTheme != null) {
+    envVarsExtra = let
+      inherit (config.home) profileDirectory;
+      qtVersions = with pkgs; [ qt5 qt6 ];
+      makeQtPath = prefix:
+        lib.concatStringsSep ":"
+        (map (qt: "${profileDirectory}/${qt.qtbase.${prefix}}") qtVersions);
+    in {
+      QT_PLUGIN_PATH = "$QT_PLUGIN_PATH\${QT_PLUGIN_PATH:+:}"
+        + (makeQtPath "qtPluginPrefix");
+      QML2_IMPORT_PATH = "$QML2_IMPORT_PATH\${QML2_IMPORT_PATH:+:}"
+        + (makeQtPath "qtQmlPrefix");
+    };
+
+  in lib.mkIf cfg.enable {
     assertions = [{
       assertion = cfg.platformTheme == "gnome" -> cfg.style.name != null
         && cfg.style.package != null;
@@ -147,37 +187,31 @@ in {
       '';
     }];
 
-    qt.style.package = mkIf (cfg.style.name != null)
-      (mkDefault (stylePackages.${toLower cfg.style.name} or null));
+    qt.style.package = lib.mkIf (cfg.style.name != null)
+      (lib.mkDefault (stylePackages.${lib.toLower cfg.style.name} or null));
 
-    home.sessionVariables = envVars;
+    home = {
+      sessionVariables = envVars;
+      # home.sessionVariables does not support setting the same environment
+      # variable to different values.
+      # Since some other modules may set the QT_PLUGIN_PATH or QML2_IMPORT_PATH
+      # to their own value, e.g.: fcitx5, we avoid conflicts by setting
+      # the values in home.sessionVariablesExtra instead.
+      sessionVariablesExtra = ''
+        export QT_PLUGIN_PATH=${envVarsExtra.QT_PLUGIN_PATH}
+        export QML2_IMPORT_PATH=${envVarsExtra.QML2_IMPORT_PATH}
+      '';
+    };
 
     # Apply theming also to apps started by systemd.
-    systemd.user.sessionVariables = envVars;
+    systemd.user.sessionVariables = envVars // envVarsExtra;
 
-    home.packages = (if cfg.platformTheme == "gnome" then
-      [ pkgs.qgnomeplatform ]
-    else if cfg.platformTheme == "qtct" then [
-      pkgs.libsForQt5.qt5ct
-      pkgs.qt6Packages.qt6ct
-    ] else if cfg.platformTheme == "kde" then [
-      pkgs.libsForQt5.plasma-integration
-      pkgs.libsForQt5.systemsettings
-    ] else
-      [ pkgs.libsForQt5.qtstyleplugins ])
+    home.packages = (platformPackages.${cfg.platformTheme} or [ ])
       ++ lib.optionals (cfg.style.package != null)
       (lib.toList cfg.style.package);
 
-    xsession.importedVariables = [ "QT_QPA_PLATFORMTHEME" ]
+    xsession.importedVariables = [ "QT_PLUGIN_PATH" "QML2_IMPORT_PATH" ]
+      ++ lib.optionals (cfg.platformTheme != null) [ "QT_QPA_PLATFORMTHEME" ]
       ++ lib.optionals (cfg.style.name != null) [ "QT_STYLE_OVERRIDE" ];
-
-    # Enable GTK+ style for Qt4 in Gtk/GNOME.
-    # It doesn’t support the platform theme packages.
-    home.activation.useGtkThemeInQt4 =
-      mkIf (cfg.platformTheme == "gtk" || cfg.platformTheme == "gnome")
-      (hm.dag.entryAfter [ "writeBoundary" ] ''
-        $DRY_RUN_CMD ${pkgs.crudini}/bin/crudini $VERBOSE_ARG \
-          --set "${config.xdg.configHome}/Trolltech.conf" Qt style GTK+
-      '');
   };
 }
diff --git a/tests/modules/misc/qt/qt-platform-theme-gnome.nix b/tests/modules/misc/qt/qt-platform-theme-gnome.nix
index 58b4cd7a1..d95ef704a 100644
--- a/tests/modules/misc/qt/qt-platform-theme-gnome.nix
+++ b/tests/modules/misc/qt/qt-platform-theme-gnome.nix
@@ -15,6 +15,10 @@
         'QT_QPA_PLATFORMTHEME="gnome"'
       assertFileRegex home-path/etc/profile.d/hm-session-vars.sh \
         'QT_STYLE_OVERRIDE="adwaita"'
+      assertFileRegex home-path/etc/profile.d/hm-session-vars.sh \
+        'QT_PLUGIN_PATH'
+      assertFileRegex home-path/etc/profile.d/hm-session-vars.sh \
+        'QML2_IMPORT_PATH'
     '';
   };
 }
diff --git a/tests/modules/misc/qt/qt-platform-theme-gtk.nix b/tests/modules/misc/qt/qt-platform-theme-gtk.nix
index d33246528..070c8020a 100644
--- a/tests/modules/misc/qt/qt-platform-theme-gtk.nix
+++ b/tests/modules/misc/qt/qt-platform-theme-gtk.nix
@@ -6,10 +6,15 @@
       enable = true;
       platformTheme = "gtk";
     };
+    i18n.inputMethod.enabled = "fcitx5";
 
     nmt.script = ''
       assertFileRegex home-path/etc/profile.d/hm-session-vars.sh \
         'QT_QPA_PLATFORMTHEME="gtk2"'
+      assertFileRegex home-path/etc/profile.d/hm-session-vars.sh \
+        'QT_PLUGIN_PATH'
+      assertFileRegex home-path/etc/profile.d/hm-session-vars.sh \
+        'QML2_IMPORT_PATH'
     '';
   };
 }