diff --git a/packages/router-generator/src/generator.ts b/packages/router-generator/src/generator.ts
index afb42941d1d..f16f953edcb 100644
--- a/packages/router-generator/src/generator.ts
+++ b/packages/router-generator/src/generator.ts
@@ -1447,9 +1447,12 @@ ${acc.routeTree.map((child) => `${child.variableName}Route: typeof ${getResolved
         const candidate = acc.routeNodesByPath.get(searchPath)
         if (candidate && !candidate.isVirtual && candidate.path !== '/') {
           node.parent = candidate
-          node.path = node.routePath
+          node.path =
+            node.routePath?.replace(candidate.routePath ?? '', '') || '/'
+          const pathRelativeToParent =
+            immediateParentPath.replace(candidate.routePath ?? '', '') || '/'
           node.cleanedPath = removeGroups(
-            removeUnderscores(removeLayoutSegments(immediateParentPath)) ?? '',
+            removeUnderscores(removeLayoutSegments(pathRelativeToParent)) ?? '',
           )
           break
         }
diff --git a/packages/router-generator/tests/generator/flat-route-group/routeTree.nonnested.snapshot.ts b/packages/router-generator/tests/generator/flat-route-group/routeTree.nonnested.snapshot.ts
new file mode 100644
index 00000000000..b0f4031474d
--- /dev/null
+++ b/packages/router-generator/tests/generator/flat-route-group/routeTree.nonnested.snapshot.ts
@@ -0,0 +1,145 @@
+/* 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'
+import { Route as AppRouteImport } from './routes/app'
+import { Route as AppcomprasComprasOrdenesRouteImport } from './routes/app.(compras)/compras_.ordenes'
+import { Route as AppcomprasComprasMasRouteImport } from './routes/app.(compras)/compras_._mas'
+import { Route as AppcomprasComprasMasDivisionesRouteImport } from './routes/app.(compras)/compras_._mas.divisiones'
+
+const AppRoute = AppRouteImport.update({
+  id: '/app',
+  path: '/app',
+  getParentRoute: () => rootRouteImport,
+} as any)
+const AppcomprasComprasOrdenesRoute =
+  AppcomprasComprasOrdenesRouteImport.update({
+    id: '/app/(compras)/compras/ordenes',
+    path: '/app/compras/ordenes',
+    getParentRoute: () => rootRouteImport,
+  } as any)
+const AppcomprasComprasMasRoute = AppcomprasComprasMasRouteImport.update({
+  id: '/(compras)/compras/_mas',
+  path: '/compras',
+  getParentRoute: () => AppRoute,
+} as any)
+const AppcomprasComprasMasDivisionesRoute =
+  AppcomprasComprasMasDivisionesRouteImport.update({
+    id: '/divisiones',
+    path: '/divisiones',
+    getParentRoute: () => AppcomprasComprasMasRoute,
+  } as any)
+
+export interface FileRoutesByFullPath {
+  '/app': typeof AppRouteWithChildren
+  '/app/compras': typeof AppcomprasComprasMasRouteWithChildren
+  '/app/compras/ordenes': typeof AppcomprasComprasOrdenesRoute
+  '/app/compras/divisiones': typeof AppcomprasComprasMasDivisionesRoute
+}
+export interface FileRoutesByTo {
+  '/app': typeof AppRouteWithChildren
+  '/app/compras': typeof AppcomprasComprasMasRouteWithChildren
+  '/app/compras/ordenes': typeof AppcomprasComprasOrdenesRoute
+  '/app/compras/divisiones': typeof AppcomprasComprasMasDivisionesRoute
+}
+export interface FileRoutesById {
+  __root__: typeof rootRouteImport
+  '/app': typeof AppRouteWithChildren
+  '/app/(compras)/compras/_mas': typeof AppcomprasComprasMasRouteWithChildren
+  '/app/(compras)/compras/ordenes': typeof AppcomprasComprasOrdenesRoute
+  '/app/(compras)/compras/_mas/divisiones': typeof AppcomprasComprasMasDivisionesRoute
+}
+export interface FileRouteTypes {
+  fileRoutesByFullPath: FileRoutesByFullPath
+  fullPaths:
+    | '/app'
+    | '/app/compras'
+    | '/app/compras/ordenes'
+    | '/app/compras/divisiones'
+  fileRoutesByTo: FileRoutesByTo
+  to:
+    | '/app'
+    | '/app/compras'
+    | '/app/compras/ordenes'
+    | '/app/compras/divisiones'
+  id:
+    | '__root__'
+    | '/app'
+    | '/app/(compras)/compras/_mas'
+    | '/app/(compras)/compras/ordenes'
+    | '/app/(compras)/compras/_mas/divisiones'
+  fileRoutesById: FileRoutesById
+}
+export interface RootRouteChildren {
+  AppRoute: typeof AppRouteWithChildren
+  AppcomprasComprasOrdenesRoute: typeof AppcomprasComprasOrdenesRoute
+}
+
+declare module '@tanstack/react-router' {
+  interface FileRoutesByPath {
+    '/app': {
+      id: '/app'
+      path: '/app'
+      fullPath: '/app'
+      preLoaderRoute: typeof AppRouteImport
+      parentRoute: typeof rootRouteImport
+    }
+    '/app/(compras)/compras/ordenes': {
+      id: '/app/(compras)/compras/ordenes'
+      path: '/app/compras/ordenes'
+      fullPath: '/app/compras/ordenes'
+      preLoaderRoute: typeof AppcomprasComprasOrdenesRouteImport
+      parentRoute: typeof rootRouteImport
+    }
+    '/app/(compras)/compras/_mas': {
+      id: '/app/(compras)/compras/_mas'
+      path: '/compras'
+      fullPath: '/app/compras'
+      preLoaderRoute: typeof AppcomprasComprasMasRouteImport
+      parentRoute: typeof AppRoute
+    }
+    '/app/(compras)/compras/_mas/divisiones': {
+      id: '/app/(compras)/compras/_mas/divisiones'
+      path: '/divisiones'
+      fullPath: '/app/compras/divisiones'
+      preLoaderRoute: typeof AppcomprasComprasMasDivisionesRouteImport
+      parentRoute: typeof AppcomprasComprasMasRoute
+    }
+  }
+}
+
+interface AppcomprasComprasMasRouteChildren {
+  AppcomprasComprasMasDivisionesRoute: typeof AppcomprasComprasMasDivisionesRoute
+}
+
+const AppcomprasComprasMasRouteChildren: AppcomprasComprasMasRouteChildren = {
+  AppcomprasComprasMasDivisionesRoute: AppcomprasComprasMasDivisionesRoute,
+}
+
+const AppcomprasComprasMasRouteWithChildren =
+  AppcomprasComprasMasRoute._addFileChildren(AppcomprasComprasMasRouteChildren)
+
+interface AppRouteChildren {
+  AppcomprasComprasMasRoute: typeof AppcomprasComprasMasRouteWithChildren
+}
+
+const AppRouteChildren: AppRouteChildren = {
+  AppcomprasComprasMasRoute: AppcomprasComprasMasRouteWithChildren,
+}
+
+const AppRouteWithChildren = AppRoute._addFileChildren(AppRouteChildren)
+
+const rootRouteChildren: RootRouteChildren = {
+  AppRoute: AppRouteWithChildren,
+  AppcomprasComprasOrdenesRoute: AppcomprasComprasOrdenesRoute,
+}
+export const routeTree = rootRouteImport
+  ._addFileChildren(rootRouteChildren)
+  ._addFileTypes<FileRouteTypes>()
diff --git a/packages/router-generator/tests/generator/flat-route-group/routeTree.snapshot.ts b/packages/router-generator/tests/generator/flat-route-group/routeTree.snapshot.ts
new file mode 100644
index 00000000000..7f7990e7870
--- /dev/null
+++ b/packages/router-generator/tests/generator/flat-route-group/routeTree.snapshot.ts
@@ -0,0 +1,147 @@
+/* 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'
+import { Route as AppRouteImport } from './routes/app'
+import { Route as AppcomprasComprasOrdenesRouteImport } from './routes/app.(compras)/compras_.ordenes'
+import { Route as AppcomprasCompras_masRouteImport } from './routes/app.(compras)/compras_._mas'
+import { Route as AppcomprasCompras_masDivisionesRouteImport } from './routes/app.(compras)/compras_._mas.divisiones'
+
+const AppRoute = AppRouteImport.update({
+  id: '/app',
+  path: '/app',
+  getParentRoute: () => rootRouteImport,
+} as any)
+const AppcomprasComprasOrdenesRoute =
+  AppcomprasComprasOrdenesRouteImport.update({
+    id: '/(compras)/compras_/ordenes',
+    path: '/compras/ordenes',
+    getParentRoute: () => AppRoute,
+  } as any)
+const AppcomprasCompras_masRoute = AppcomprasCompras_masRouteImport.update({
+  id: '/(compras)/compras_/_mas',
+  path: '/compras',
+  getParentRoute: () => AppRoute,
+} as any)
+const AppcomprasCompras_masDivisionesRoute =
+  AppcomprasCompras_masDivisionesRouteImport.update({
+    id: '/divisiones',
+    path: '/divisiones',
+    getParentRoute: () => AppcomprasCompras_masRoute,
+  } as any)
+
+export interface FileRoutesByFullPath {
+  '/app': typeof AppRouteWithChildren
+  '/app/compras': typeof AppcomprasCompras_masRouteWithChildren
+  '/app/compras/ordenes': typeof AppcomprasComprasOrdenesRoute
+  '/app/compras/divisiones': typeof AppcomprasCompras_masDivisionesRoute
+}
+export interface FileRoutesByTo {
+  '/app': typeof AppRouteWithChildren
+  '/app/compras': typeof AppcomprasCompras_masRouteWithChildren
+  '/app/compras/ordenes': typeof AppcomprasComprasOrdenesRoute
+  '/app/compras/divisiones': typeof AppcomprasCompras_masDivisionesRoute
+}
+export interface FileRoutesById {
+  __root__: typeof rootRouteImport
+  '/app': typeof AppRouteWithChildren
+  '/app/(compras)/compras_/_mas': typeof AppcomprasCompras_masRouteWithChildren
+  '/app/(compras)/compras_/ordenes': typeof AppcomprasComprasOrdenesRoute
+  '/app/(compras)/compras_/_mas/divisiones': typeof AppcomprasCompras_masDivisionesRoute
+}
+export interface FileRouteTypes {
+  fileRoutesByFullPath: FileRoutesByFullPath
+  fullPaths:
+    | '/app'
+    | '/app/compras'
+    | '/app/compras/ordenes'
+    | '/app/compras/divisiones'
+  fileRoutesByTo: FileRoutesByTo
+  to:
+    | '/app'
+    | '/app/compras'
+    | '/app/compras/ordenes'
+    | '/app/compras/divisiones'
+  id:
+    | '__root__'
+    | '/app'
+    | '/app/(compras)/compras_/_mas'
+    | '/app/(compras)/compras_/ordenes'
+    | '/app/(compras)/compras_/_mas/divisiones'
+  fileRoutesById: FileRoutesById
+}
+export interface RootRouteChildren {
+  AppRoute: typeof AppRouteWithChildren
+}
+
+declare module '@tanstack/react-router' {
+  interface FileRoutesByPath {
+    '/app': {
+      id: '/app'
+      path: '/app'
+      fullPath: '/app'
+      preLoaderRoute: typeof AppRouteImport
+      parentRoute: typeof rootRouteImport
+    }
+    '/app/(compras)/compras_/ordenes': {
+      id: '/app/(compras)/compras_/ordenes'
+      path: '/compras/ordenes'
+      fullPath: '/app/compras/ordenes'
+      preLoaderRoute: typeof AppcomprasComprasOrdenesRouteImport
+      parentRoute: typeof AppRoute
+    }
+    '/app/(compras)/compras_/_mas': {
+      id: '/app/(compras)/compras_/_mas'
+      path: '/compras'
+      fullPath: '/app/compras'
+      preLoaderRoute: typeof AppcomprasCompras_masRouteImport
+      parentRoute: typeof AppRoute
+    }
+    '/app/(compras)/compras_/_mas/divisiones': {
+      id: '/app/(compras)/compras_/_mas/divisiones'
+      path: '/divisiones'
+      fullPath: '/app/compras/divisiones'
+      preLoaderRoute: typeof AppcomprasCompras_masDivisionesRouteImport
+      parentRoute: typeof AppcomprasCompras_masRoute
+    }
+  }
+}
+
+interface AppcomprasCompras_masRouteChildren {
+  AppcomprasCompras_masDivisionesRoute: typeof AppcomprasCompras_masDivisionesRoute
+}
+
+const AppcomprasCompras_masRouteChildren: AppcomprasCompras_masRouteChildren = {
+  AppcomprasCompras_masDivisionesRoute: AppcomprasCompras_masDivisionesRoute,
+}
+
+const AppcomprasCompras_masRouteWithChildren =
+  AppcomprasCompras_masRoute._addFileChildren(
+    AppcomprasCompras_masRouteChildren,
+  )
+
+interface AppRouteChildren {
+  AppcomprasCompras_masRoute: typeof AppcomprasCompras_masRouteWithChildren
+  AppcomprasComprasOrdenesRoute: typeof AppcomprasComprasOrdenesRoute
+}
+
+const AppRouteChildren: AppRouteChildren = {
+  AppcomprasCompras_masRoute: AppcomprasCompras_masRouteWithChildren,
+  AppcomprasComprasOrdenesRoute: AppcomprasComprasOrdenesRoute,
+}
+
+const AppRouteWithChildren = AppRoute._addFileChildren(AppRouteChildren)
+
+const rootRouteChildren: RootRouteChildren = {
+  AppRoute: AppRouteWithChildren,
+}
+export const routeTree = rootRouteImport
+  ._addFileChildren(rootRouteChildren)
+  ._addFileTypes<FileRouteTypes>()
diff --git a/packages/router-generator/tests/generator/flat-route-group/routes/__root.tsx b/packages/router-generator/tests/generator/flat-route-group/routes/__root.tsx
new file mode 100644
index 00000000000..a8c4d4c8938
--- /dev/null
+++ b/packages/router-generator/tests/generator/flat-route-group/routes/__root.tsx
@@ -0,0 +1,2 @@
+// @ts-nocheck
+export const Route = createFileRoute()
diff --git a/packages/router-generator/tests/generator/flat-route-group/routes/app.(compras)/compras_._mas.divisiones.tsx b/packages/router-generator/tests/generator/flat-route-group/routes/app.(compras)/compras_._mas.divisiones.tsx
new file mode 100644
index 00000000000..ebec0274136
--- /dev/null
+++ b/packages/router-generator/tests/generator/flat-route-group/routes/app.(compras)/compras_._mas.divisiones.tsx
@@ -0,0 +1,11 @@
+import { createFileRoute } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/app/(compras)/compras_/_mas/divisiones')(
+  {
+    component: RouteComponent,
+  },
+)
+
+function RouteComponent() {
+  return <div>Hello "/app/(compras)/compras/_mas/divisiones"!</div>
+}
diff --git a/packages/router-generator/tests/generator/flat-route-group/routes/app.(compras)/compras_._mas.tsx b/packages/router-generator/tests/generator/flat-route-group/routes/app.(compras)/compras_._mas.tsx
new file mode 100644
index 00000000000..a10276884a6
--- /dev/null
+++ b/packages/router-generator/tests/generator/flat-route-group/routes/app.(compras)/compras_._mas.tsx
@@ -0,0 +1,9 @@
+import { createFileRoute } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/app/(compras)/compras_/_mas')({
+  component: RouteComponent,
+})
+
+function RouteComponent() {
+  return <div>Hello "/app/(compras)/compras/mas"!</div>
+}
diff --git a/packages/router-generator/tests/generator/flat-route-group/routes/app.(compras)/compras_.ordenes.tsx b/packages/router-generator/tests/generator/flat-route-group/routes/app.(compras)/compras_.ordenes.tsx
new file mode 100644
index 00000000000..ce1a19c9add
--- /dev/null
+++ b/packages/router-generator/tests/generator/flat-route-group/routes/app.(compras)/compras_.ordenes.tsx
@@ -0,0 +1,9 @@
+import { createFileRoute } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/app/(compras)/compras_/ordenes')({
+  component: RouteComponent,
+})
+
+function RouteComponent() {
+  return <div>Hello "/app/(compras)/compras/mas/divisiones"!</div>
+}
diff --git a/packages/router-generator/tests/generator/flat-route-group/routes/app.tsx b/packages/router-generator/tests/generator/flat-route-group/routes/app.tsx
new file mode 100644
index 00000000000..fdc75fcb17f
--- /dev/null
+++ b/packages/router-generator/tests/generator/flat-route-group/routes/app.tsx
@@ -0,0 +1,9 @@
+import { createFileRoute } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/app')({
+  component: RouteComponent,
+})
+
+function RouteComponent() {
+  return <div>Hello "/app"!</div>
+}