diff --git a/.changeset/virtual-pathless-layout-dotted-filename.md b/.changeset/virtual-pathless-layout-dotted-filename.md
new file mode 100644
index 0000000000..eca8a4f8d2
--- /dev/null
+++ b/.changeset/virtual-pathless-layout-dotted-filename.md
@@ -0,0 +1,9 @@
+---
+'@tanstack/router-generator': patch
+---
+
+fix(router-generator): keep dotted virtual pathless layout filenames as one segment
+
+`layout('pathless.layout.tsx')` was running the layout id through `determineInitialRoutePath`, which treats unescaped dots as path separators. That turned `_pathless.layout` into `/_pathless/layout` and mounted children under a real `/layout` URL segment. Dots in layout ids are now escaped so the id stays a single pathless segment and children keep their original paths (e.g. `/subpath`).
+
+Fixes #7761.
diff --git a/packages/router-generator/src/filesystem/virtual/getRouteNodes.ts b/packages/router-generator/src/filesystem/virtual/getRouteNodes.ts
index 509b1be321..fafb6f4f1b 100644
--- a/packages/router-generator/src/filesystem/virtual/getRouteNodes.ts
+++ b/packages/router-generator/src/filesystem/virtual/getRouteNodes.ts
@@ -301,11 +301,21 @@ export async function getRouteNodesRecursive(
             node.id = ensureLeadingUnderScore(fileNameWithoutExt)
           }
           const lastSegment = node.id
+          // Layout ids from filenames like `pathless.layout.tsx` become
+          // `_pathless.layout`. Those dots are part of the identifier, not
+          // path separators — if we pass them through determineInitialRoutePath
+          // raw, SPLIT_REGEX turns them into `/` and children mount under a
+          // real `/layout` URL segment (regression from 1.145.1, #7761).
+          // Escape unbracketed dots so the id stays one pathless segment.
+          const segmentForPath = removeLeadingSlash(lastSegment).replace(
+            /(?<!\[)\.(?!\])/g,
+            '[.]',
+          )
           // Process the segment to handle escape sequences like [_]
           const {
             routePath: escapedSegment,
             originalRoutePath: originalSegment,
-          } = determineInitialRoutePath(removeLeadingSlash(lastSegment))
+          } = determineInitialRoutePath(segmentForPath)
           const routePath = `${parentRoutePath}${escapedSegment}`
           // Store the original path with brackets for escape detection
           const originalRoutePath = `${parentOriginalRoutePath}${originalSegment}`
diff --git a/packages/router-generator/tests/generator.test.ts b/packages/router-generator/tests/generator.test.ts
index 79f7d505b2..6614003933 100644
--- a/packages/router-generator/tests/generator.test.ts
+++ b/packages/router-generator/tests/generator.test.ts
@@ -166,6 +166,20 @@ function rewriteConfigByFolderName(folderName: string, config: Config) {
         config.virtualRouteConfig = virtualRouteConfig
       }
       break
+    case 'virtual-pathless-layout-dotted-filename':
+      {
+        // Issue #7761: layout() whose filename contains a dot (pathless.layout.tsx)
+        // must stay a single pathless segment so children keep their URL
+        // (/subpath), not mount under a leaked /layout segment.
+        const virtualRouteConfig = rootRoute('root.route.tsx', [
+          index('index.route.tsx'),
+          layout('pathless.layout.tsx', [
+            route('subpath', 'subpath.route.tsx'),
+          ]),
+        ])
+        config.virtualRouteConfig = virtualRouteConfig
+      }
+      break
     case 'virtual-root-sibling-routes':
       {
         // Test case for issue #5431: Virtual routes that are siblings at the root level
diff --git a/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routeTree.snapshot.ts b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routeTree.snapshot.ts
new file mode 100644
index 0000000000..c09aad1198
--- /dev/null
+++ b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routeTree.snapshot.ts
@@ -0,0 +1,101 @@
+/* eslint-disable */
+
+// @ts-nocheck
+
+// noinspection JSUnusedGlobalSymbols
+
+// This file was automatically generated by TanStack Router.
+// You should NOT make any changes in this file as it will be overwritten.
+// Additionally, you should also exclude this file from your linter and/or formatter to prevent it from being checked or modified.
+
+import { Route as rootRouteImport } from './routes/root.route'
+import { Route as pathlessDotlayoutRouteImport } from './routes/pathless.layout'
+import { Route as indexDotrouteRouteImport } from './routes/index.route'
+import { Route as subpathDotrouteRouteImport } from './routes/subpath.route'
+
+const pathlessDotlayoutRoute = pathlessDotlayoutRouteImport.update({
+  id: '/_pathless.layout',
+  getParentRoute: () => rootRouteImport,
+} as any)
+const indexDotrouteRoute = indexDotrouteRouteImport.update({
+  id: '/',
+  path: '/',
+  getParentRoute: () => rootRouteImport,
+} as any)
+const subpathDotrouteRoute = subpathDotrouteRouteImport.update({
+  id: '/subpath',
+  path: '/subpath',
+  getParentRoute: () => pathlessDotlayoutRoute,
+} as any)
+
+export interface FileRoutesByFullPath {
+  '/': typeof indexDotrouteRoute
+  '/subpath': typeof subpathDotrouteRoute
+}
+export interface FileRoutesByTo {
+  '/': typeof indexDotrouteRoute
+  '/subpath': typeof subpathDotrouteRoute
+}
+export interface FileRoutesById {
+  __root__: typeof rootRouteImport
+  '/': typeof indexDotrouteRoute
+  '/_pathless.layout': typeof pathlessDotlayoutRouteWithChildren
+  '/_pathless.layout/subpath': typeof subpathDotrouteRoute
+}
+export interface FileRouteTypes {
+  fileRoutesByFullPath: FileRoutesByFullPath
+  fullPaths: '/' | '/subpath'
+  fileRoutesByTo: FileRoutesByTo
+  to: '/' | '/subpath'
+  id: '__root__' | '/' | '/_pathless.layout' | '/_pathless.layout/subpath'
+  fileRoutesById: FileRoutesById
+}
+export interface RootRouteChildren {
+  indexDotrouteRoute: typeof indexDotrouteRoute
+  pathlessDotlayoutRoute: typeof pathlessDotlayoutRouteWithChildren
+}
+
+declare module '@tanstack/react-router' {
+  interface FileRoutesByPath {
+    '/_pathless.layout': {
+      id: '/_pathless.layout'
+      path: ''
+      fullPath: '/'
+      preLoaderRoute: typeof pathlessDotlayoutRouteImport
+      parentRoute: typeof rootRouteImport
+    }
+    '/': {
+      id: '/'
+      path: '/'
+      fullPath: '/'
+      preLoaderRoute: typeof indexDotrouteRouteImport
+      parentRoute: typeof rootRouteImport
+    }
+    '/_pathless.layout/subpath': {
+      id: '/_pathless.layout/subpath'
+      path: '/subpath'
+      fullPath: '/subpath'
+      preLoaderRoute: typeof subpathDotrouteRouteImport
+      parentRoute: typeof pathlessDotlayoutRoute
+    }
+  }
+}
+
+interface pathlessDotlayoutRouteChildren {
+  subpathDotrouteRoute: typeof subpathDotrouteRoute
+}
+
+const pathlessDotlayoutRouteChildren: pathlessDotlayoutRouteChildren = {
+  subpathDotrouteRoute: subpathDotrouteRoute,
+}
+
+const pathlessDotlayoutRouteWithChildren =
+  pathlessDotlayoutRoute._addFileChildren(pathlessDotlayoutRouteChildren)
+
+const rootRouteChildren: RootRouteChildren = {
+  indexDotrouteRoute: indexDotrouteRoute,
+  pathlessDotlayoutRoute: pathlessDotlayoutRouteWithChildren,
+}
+export const routeTree = rootRouteImport
+  ._addFileChildren(rootRouteChildren)
+  ._addFileTypes<FileRouteTypes>()
diff --git a/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/index.route.tsx b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/index.route.tsx
new file mode 100644
index 0000000000..379428d7b2
--- /dev/null
+++ b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/index.route.tsx
@@ -0,0 +1,5 @@
+import { createFileRoute } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/')({
+  component: () => 'Index',
+})
diff --git a/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/pathless.layout.tsx b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/pathless.layout.tsx
new file mode 100644
index 0000000000..3e0a504adc
--- /dev/null
+++ b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/pathless.layout.tsx
@@ -0,0 +1,5 @@
+import { createFileRoute } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/_pathless.layout')({
+  component: () => 'PathlessLayout',
+})
diff --git a/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/root.route.tsx b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/root.route.tsx
new file mode 100644
index 0000000000..9c657c7d5b
--- /dev/null
+++ b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/root.route.tsx
@@ -0,0 +1,3 @@
+import { createRootRoute } from '@tanstack/react-router'
+
+export const Route = createRootRoute()
diff --git a/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/subpath.route.tsx b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/subpath.route.tsx
new file mode 100644
index 0000000000..6c28fa210f
--- /dev/null
+++ b/packages/router-generator/tests/generator/virtual-pathless-layout-dotted-filename/routes/subpath.route.tsx
@@ -0,0 +1,5 @@
+import { createFileRoute } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/_pathless.layout/subpath')({
+  component: () => 'Subpath',
+})