diff --git a/installer/Package.wxs b/installer/Package.wxs
new file mode 100644
index 0000000..b1b7233
--- /dev/null
+++ b/installer/Package.wxs
@@ -0,0 +1,146 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+    TeamsISO — MSI installer (WiX v5)
+
+    Produces: TeamsISO-Setup-<Version>.msi (per-machine install).
+
+    Build:
+        dotnet publish src/TeamsISO.App/TeamsISO.App.csproj -c Release -r win-x64 (no self contained) -o publish/TeamsISO
+        dotnet build installer/TeamsISO.Installer.wixproj -c Release
+
+    Runtime expectations:
+        - .NET 8 Desktop runtime present on target (framework-dependent build)
+        - NDI 6 Runtime present — checked in CheckNdiRuntime; absence WARNS
+          but does not block install (operators can install NDI after the app)
+-->
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs"
+     xmlns:ui="http://wixtoolset.org/schemas/v4/wxs/ui">
+
+  <Package Name="TeamsISO"
+           Manufacturer="Wild Dragon LLC"
+           Version="1.0.0.0"
+           UpgradeCode="9F4A8B2C-1D3E-4A5B-9C6D-8E7F0A1B2C3D"
+           Scope="perMachine"
+           Compressed="yes"
+           InstallerVersion="500">
+
+    <SummaryInformation Description="TeamsISO — Per-Participant NDI ISO Controller for Microsoft Teams"
+                        Manufacturer="Wild Dragon LLC" />
+
+    <!--
+        MajorUpgrade: a newer install replaces an older one in-place.
+        Disallow downgrades; users should uninstall the newer first.
+    -->
+    <MajorUpgrade DowngradeErrorMessage="A newer version of TeamsISO is already installed. Uninstall it before installing this older version."
+                  Schedule="afterInstallInitialize" />
+
+    <!--
+        Single MSI feature; users see only the install/uninstall screens.
+    -->
+    <Feature Id="Main" Title="TeamsISO" Level="1">
+      <ComponentGroupRef Id="ApplicationFiles" />
+      <ComponentGroupRef Id="Shortcuts" />
+      <ComponentGroupRef Id="ArpEntry" />
+    </Feature>
+
+    <!--
+        Friendly install UI. WixToolset.UI.wixext provides several flavors;
+        WixUI_InstallDir lets the user pick the directory.
+    -->
+    <ui:WixUI Id="WixUI_InstallDir" />
+    <Property Id="WIXUI_INSTALLDIR" Value="INSTALLFOLDER" />
+
+    <!--
+        ARP icon + about-box link.
+    -->
+    <Property Id="ARPHELPLINK" Value="https://wilddragon.net" />
+    <Property Id="ARPURLINFOABOUT" Value="https://wilddragon.net" />
+    <!-- ARPNOMODIFY is set by WixUI_InstallDir; don't redeclare. -->
+    <Property Id="ARPNOREPAIR" Value="1" />
+
+    <!--
+        NDI Runtime detection. We check for NDI_RUNTIME_DIR_V6 in the system
+        environment block. Missing → warn during install, don't block. The
+        engine surfaces a clear MessageBox with an install-NDI link at first
+        launch if the runtime really isn't there.
+    -->
+    <Property Id="NDIRUNTIMEDIR" Value="0">
+      <RegistrySearch Id="NdiRuntimeDirV6Search"
+                      Root="HKLM"
+                      Key="SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
+                      Name="NDI_RUNTIME_DIR_V6"
+                      Type="raw" />
+    </Property>
+
+    <!--
+        NDI runtime detection is surfaced at first app launch (App.xaml.cs pops a
+        MessageBox with an install link). We deliberately don't block install on
+        a missing runtime so admins can stage the app before NDI is rolled out.
+        VBScript-based install-time prompts are deprecated in WiX v5 / Windows
+        and rewriting in C++ is overkill for a soft warning.
+    -->
+
+    <!--
+        Install layout under Program Files\Wild Dragon\TeamsISO.
+    -->
+    <StandardDirectory Id="ProgramFiles64Folder">
+      <Directory Id="ManufacturerFolder" Name="Wild Dragon">
+        <Directory Id="INSTALLFOLDER" Name="TeamsISO" />
+      </Directory>
+    </StandardDirectory>
+
+    <StandardDirectory Id="ProgramMenuFolder">
+      <Directory Id="WildDragonStartMenuFolder" Name="Wild Dragon" />
+    </StandardDirectory>
+
+    <!--
+        Files: harvested from the publish output dir at build time.
+        WiX v5 understands <Files Include="..."> with glob patterns and
+        synthesizes one Component per file with stable GUIDs.
+    -->
+    <ComponentGroup Id="ApplicationFiles" Directory="INSTALLFOLDER">
+      <Files Include="$(var.PublishDir)**" />
+    </ComponentGroup>
+
+    <!--
+        Start Menu shortcut to the WPF host. KeyPath sits on a registry
+        value so component identity is stable across upgrades.
+    -->
+    <ComponentGroup Id="Shortcuts" Directory="WildDragonStartMenuFolder">
+      <Component Id="StartMenuShortcut" Guid="*">
+        <Shortcut Id="StartMenuTeamsISO"
+                  Name="TeamsISO"
+                  Description="Per-Participant NDI ISO Controller for Microsoft Teams"
+                  Target="[INSTALLFOLDER]TeamsISO.exe"
+                  WorkingDirectory="INSTALLFOLDER" />
+        <!-- Required by ICE64: Start Menu folder must be cleaned on uninstall. -->
+        <RemoveFolder Id="RemoveWildDragonStartMenuFolder"
+                      Directory="WildDragonStartMenuFolder"
+                      On="uninstall" />
+        <RegistryValue Root="HKCU"
+                       Key="Software\Wild Dragon\TeamsISO"
+                       Name="StartMenuShortcut"
+                       Type="integer"
+                       Value="1"
+                       KeyPath="yes" />
+      </Component>
+    </ComponentGroup>
+
+    <!--
+        ARP icon registry entry. Optional — the MSI auto-fills most ARP
+        fields from the Package element. We only need to point at the
+        executable for the ARP icon.
+    -->
+    <ComponentGroup Id="ArpEntry" Directory="INSTALLFOLDER">
+      <Component Id="ArpIconRegistry" Guid="*">
+        <RegistryValue Root="HKLM"
+                       Key="Software\Wild Dragon\TeamsISO"
+                       Name="InstallPath"
+                       Type="string"
+                       Value="[INSTALLFOLDER]"
+                       KeyPath="yes" />
+      </Component>
+    </ComponentGroup>
+
+  </Package>
+</Wix>
diff --git a/installer/TeamsISO.Installer.wixproj b/installer/TeamsISO.Installer.wixproj
new file mode 100644
index 0000000..bb304e6
--- /dev/null
+++ b/installer/TeamsISO.Installer.wixproj
@@ -0,0 +1,35 @@
+<Project Sdk="WixToolset.Sdk/5.0.2">
+
+  <PropertyGroup>
+    <OutputType>Package</OutputType>
+    <OutputName>TeamsISO-Setup-$(Version)</OutputName>
+
+    <!-- 64-bit MSI; suppresses ICE80 on components in Program Files (x64). -->
+    <Platform>x64</Platform>
+    <InstallerPlatform>x64</InstallerPlatform>
+
+    <!--
+      Built artifact location. The installer expects a published build of
+      TeamsISO.App rooted here. CI / local script:
+        dotnet publish src/TeamsISO.App/TeamsISO.App.csproj
+            -c Release -r win-x64 (with self contained false)
+            -o $(SolutionDir)publish/TeamsISO
+    -->
+    <PublishDir>$(MSBuildThisFileDirectory)..\publish\TeamsISO\</PublishDir>
+
+    <!-- Pass MSBuild values into WiX preprocessor. -->
+    <DefineConstants>PublishDir=$(PublishDir)</DefineConstants>
+
+    <!-- Code-signing hook (set externally for release builds; left empty for dev). -->
+    <SignOutput Condition=" '$(SignOutput)' == '' ">false</SignOutput>
+  </PropertyGroup>
+
+  <!--
+    Reference the WiX UI extension so the MSI shows a friendly progress UI
+    instead of the silent default.
+  -->
+  <ItemGroup>
+    <PackageReference Include="WixToolset.UI.wixext" Version="5.0.2" />
+  </ItemGroup>
+
+</Project>