diff --git a/src/Umbraco.Core/Routing/UmbracoRequestPaths.cs b/src/Umbraco.Core/Routing/UmbracoRequestPaths.cs
index b70970673a31..f31b9fca0608 100644
--- a/src/Umbraco.Core/Routing/UmbracoRequestPaths.cs
+++ b/src/Umbraco.Core/Routing/UmbracoRequestPaths.cs
@@ -148,7 +148,10 @@ private static bool IsPluginControllerRoute(string path)
     /// <summary>
     ///     Checks if the current uri is an install request
     /// </summary>
-    public bool IsInstallerRequest(string absPath) => absPath.InvariantStartsWith(_installPath);
+    public bool IsInstallerRequest(string absPath) =>
+        absPath.InvariantEquals(_installPath)
+        || absPath.InvariantStartsWith(_installPath.EnsureEndsWith('/'))
+        || absPath.InvariantStartsWith(_installPath.EnsureEndsWith('?'));
 
     /// <summary>
     ///     Rudimentary check to see if it's not a server side request
diff --git a/tests/Umbraco.Tests.UnitTests/Umbraco.Core/Routing/UmbracoRequestPathsTests.cs b/tests/Umbraco.Tests.UnitTests/Umbraco.Core/Routing/UmbracoRequestPathsTests.cs
index d4856c2b1213..9c0e4cbb16f0 100644
--- a/tests/Umbraco.Tests.UnitTests/Umbraco.Core/Routing/UmbracoRequestPathsTests.cs
+++ b/tests/Umbraco.Tests.UnitTests/Umbraco.Core/Routing/UmbracoRequestPathsTests.cs
@@ -102,9 +102,15 @@ public void Is_Back_Office_Request(string input, string virtualPath, bool expect
     [TestCase("http://www.domain.com/install/test/test", true)]
     [TestCase("http://www.domain.com/Install/test/test.aspx", true)]
     [TestCase("http://www.domain.com/install/test/test.js", true)]
+    [TestCase("http://www.domain.com/install?param=value", true)]
     [TestCase("http://www.domain.com/instal", false)]
     [TestCase("http://www.domain.com/umbraco", false)]
     [TestCase("http://www.domain.com/umbraco/umbraco", false)]
+    [TestCase("http://www.domain.com/installation", false)]
+    [TestCase("http://www.domain.com/installation/", false)]
+    [TestCase("http://www.domain.com/installation/test", false)]
+    [TestCase("http://www.domain.com/installation/test.js", false)]
+    [TestCase("http://www.domain.com/installation?param=value", false)]
     public void Is_Installer_Request(string input, bool expected)
     {
         var source = new Uri(input);