diff --git a/apps/api/src/controllers/usuarios.controller.ts b/apps/api/src/controllers/usuarios.controller.ts
index 57cf2c9..fc049ce 100644
--- a/apps/api/src/controllers/usuarios.controller.ts
+++ b/apps/api/src/controllers/usuarios.controller.ts
@@ -1,6 +1,21 @@
 import { Request, Response, NextFunction } from 'express';
 import * as usuariosService from '../services/usuarios.service.js';
 import { AppError } from '../utils/errors.js';
+import { prisma } from '../config/database.js';
+
+// RFC del tenant administrador global
+const ADMIN_TENANT_RFC = 'AASI940812GM6';
+
+async function isGlobalAdmin(req: Request): Promise<boolean> {
+  if (req.user!.role !== 'admin') return false;
+
+  const tenant = await prisma.tenant.findUnique({
+    where: { id: req.user!.tenantId },
+    select: { rfc: true },
+  });
+
+  return tenant?.rfc === ADMIN_TENANT_RFC;
+}
 
 export async function getUsuarios(req: Request, res: Response, next: NextFunction) {
   try {
@@ -11,6 +26,21 @@ export async function getUsuarios(req: Request, res: Response, next: NextFunctio
   }
 }
 
+/**
+ * Obtiene todos los usuarios de todas las empresas (solo admin global)
+ */
+export async function getAllUsuarios(req: Request, res: Response, next: NextFunction) {
+  try {
+    if (!(await isGlobalAdmin(req))) {
+      throw new AppError(403, 'Solo el administrador global puede ver todos los usuarios');
+    }
+    const usuarios = await usuariosService.getAllUsuarios();
+    res.json(usuarios);
+  } catch (error) {
+    next(error);
+  }
+}
+
 export async function inviteUsuario(req: Request, res: Response, next: NextFunction) {
   try {
     if (req.user!.role !== 'admin') {
@@ -28,7 +58,8 @@ export async function updateUsuario(req: Request, res: Response, next: NextFunct
     if (req.user!.role !== 'admin') {
       throw new AppError(403, 'Solo administradores pueden modificar usuarios');
     }
-    const usuario = await usuariosService.updateUsuario(req.user!.tenantId, req.params.id, req.body);
+    const userId = req.params.id as string;
+    const usuario = await usuariosService.updateUsuario(req.user!.tenantId, userId, req.body);
     res.json(usuario);
   } catch (error) {
     next(error);
@@ -40,10 +71,49 @@ export async function deleteUsuario(req: Request, res: Response, next: NextFunct
     if (req.user!.role !== 'admin') {
       throw new AppError(403, 'Solo administradores pueden eliminar usuarios');
     }
-    if (req.params.id === req.user!.id) {
+    const userId = req.params.id as string;
+    if (userId === req.user!.userId) {
       throw new AppError(400, 'No puedes eliminar tu propia cuenta');
     }
-    await usuariosService.deleteUsuario(req.user!.tenantId, req.params.id);
+    await usuariosService.deleteUsuario(req.user!.tenantId, userId);
+    res.status(204).send();
+  } catch (error) {
+    next(error);
+  }
+}
+
+/**
+ * Actualiza un usuario globalmente (puede cambiar de empresa)
+ */
+export async function updateUsuarioGlobal(req: Request, res: Response, next: NextFunction) {
+  try {
+    if (!(await isGlobalAdmin(req))) {
+      throw new AppError(403, 'Solo el administrador global puede modificar usuarios globalmente');
+    }
+    const userId = req.params.id as string;
+    if (userId === req.user!.userId && req.body.tenantId) {
+      throw new AppError(400, 'No puedes cambiar tu propia empresa');
+    }
+    const usuario = await usuariosService.updateUsuarioGlobal(userId, req.body);
+    res.json(usuario);
+  } catch (error) {
+    next(error);
+  }
+}
+
+/**
+ * Elimina un usuario globalmente
+ */
+export async function deleteUsuarioGlobal(req: Request, res: Response, next: NextFunction) {
+  try {
+    if (!(await isGlobalAdmin(req))) {
+      throw new AppError(403, 'Solo el administrador global puede eliminar usuarios globalmente');
+    }
+    const userId = req.params.id as string;
+    if (userId === req.user!.userId) {
+      throw new AppError(400, 'No puedes eliminar tu propia cuenta');
+    }
+    await usuariosService.deleteUsuarioGlobal(userId);
     res.status(204).send();
   } catch (error) {
     next(error);
diff --git a/apps/api/src/routes/usuarios.routes.ts b/apps/api/src/routes/usuarios.routes.ts
index a9804e0..35733b9 100644
--- a/apps/api/src/routes/usuarios.routes.ts
+++ b/apps/api/src/routes/usuarios.routes.ts
@@ -6,9 +6,15 @@ const router = Router();
 
 router.use(authenticate);
 
+// Rutas por tenant
 router.get('/', usuariosController.getUsuarios);
 router.post('/invite', usuariosController.inviteUsuario);
 router.patch('/:id', usuariosController.updateUsuario);
 router.delete('/:id', usuariosController.deleteUsuario);
 
+// Rutas globales (solo admin global)
+router.get('/global/all', usuariosController.getAllUsuarios);
+router.patch('/global/:id', usuariosController.updateUsuarioGlobal);
+router.delete('/global/:id', usuariosController.deleteUsuarioGlobal);
+
 export { router as usuariosRoutes };
diff --git a/apps/api/src/services/usuarios.service.ts b/apps/api/src/services/usuarios.service.ts
index 21129b5..db6bf61 100644
--- a/apps/api/src/services/usuarios.service.ts
+++ b/apps/api/src/services/usuarios.service.ts
@@ -105,3 +105,93 @@ export async function deleteUsuario(tenantId: string, userId: string): Promise<v
     where: { id: userId, tenantId },
   });
 }
+
+/**
+ * Obtiene todos los usuarios de todas las empresas (solo admin global)
+ */
+export async function getAllUsuarios(): Promise<UserListItem[]> {
+  const users = await prisma.user.findMany({
+    select: {
+      id: true,
+      email: true,
+      nombre: true,
+      role: true,
+      active: true,
+      lastLogin: true,
+      createdAt: true,
+      tenantId: true,
+      tenant: {
+        select: {
+          nombre: true,
+        },
+      },
+    },
+    orderBy: [{ tenant: { nombre: 'asc' } }, { createdAt: 'desc' }],
+  });
+
+  return users.map(u => ({
+    id: u.id,
+    email: u.email,
+    nombre: u.nombre,
+    role: u.role,
+    active: u.active,
+    lastLogin: u.lastLogin?.toISOString() || null,
+    createdAt: u.createdAt.toISOString(),
+    tenantId: u.tenantId,
+    tenantName: u.tenant.nombre,
+  }));
+}
+
+/**
+ * Actualiza un usuario globalmente (puede cambiar de tenant)
+ */
+export async function updateUsuarioGlobal(
+  userId: string,
+  data: UserUpdate & { tenantId?: string }
+): Promise<UserListItem> {
+  const user = await prisma.user.update({
+    where: { id: userId },
+    data: {
+      ...(data.nombre && { nombre: data.nombre }),
+      ...(data.role && { role: data.role }),
+      ...(data.active !== undefined && { active: data.active }),
+      ...(data.tenantId && { tenantId: data.tenantId }),
+    },
+    select: {
+      id: true,
+      email: true,
+      nombre: true,
+      role: true,
+      active: true,
+      lastLogin: true,
+      createdAt: true,
+      tenantId: true,
+      tenant: {
+        select: {
+          nombre: true,
+        },
+      },
+    },
+  });
+
+  return {
+    id: user.id,
+    email: user.email,
+    nombre: user.nombre,
+    role: user.role,
+    active: user.active,
+    lastLogin: user.lastLogin?.toISOString() || null,
+    createdAt: user.createdAt.toISOString(),
+    tenantId: user.tenantId,
+    tenantName: user.tenant.nombre,
+  };
+}
+
+/**
+ * Elimina un usuario globalmente
+ */
+export async function deleteUsuarioGlobal(userId: string): Promise<void> {
+  await prisma.user.delete({
+    where: { id: userId },
+  });
+}
diff --git a/apps/web/app/(dashboard)/admin/usuarios/page.tsx b/apps/web/app/(dashboard)/admin/usuarios/page.tsx
new file mode 100644
index 0000000..8b576bc
--- /dev/null
+++ b/apps/web/app/(dashboard)/admin/usuarios/page.tsx
@@ -0,0 +1,305 @@
+'use client';
+
+import { useState, useEffect } from 'react';
+import { DashboardShell } from '@/components/layouts/dashboard-shell';
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
+import { Button } from '@/components/ui/button';
+import { Input } from '@/components/ui/input';
+import { Label } from '@/components/ui/label';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+import { useAllUsuarios, useUpdateUsuarioGlobal, useDeleteUsuarioGlobal } from '@/lib/hooks/use-usuarios';
+import { getTenants, type Tenant } from '@/lib/api/tenants';
+import { useAuthStore } from '@/stores/auth-store';
+import { Users, Pencil, Trash2, Shield, Eye, Calculator, Building2, X, Check } from 'lucide-react';
+import { cn } from '@/lib/utils';
+
+const roleLabels = {
+  admin: { label: 'Administrador', icon: Shield, color: 'text-primary' },
+  contador: { label: 'Contador', icon: Calculator, color: 'text-green-600' },
+  visor: { label: 'Visor', icon: Eye, color: 'text-muted-foreground' },
+};
+
+interface EditingUser {
+  id: string;
+  nombre: string;
+  role: 'admin' | 'contador' | 'visor';
+  tenantId: string;
+}
+
+export default function AdminUsuariosPage() {
+  const { user: currentUser } = useAuthStore();
+  const { data: usuarios, isLoading, error } = useAllUsuarios();
+  const updateUsuario = useUpdateUsuarioGlobal();
+  const deleteUsuario = useDeleteUsuarioGlobal();
+
+  const [tenants, setTenants] = useState<Tenant[]>([]);
+  const [editingUser, setEditingUser] = useState<EditingUser | null>(null);
+  const [filterTenant, setFilterTenant] = useState<string>('all');
+  const [searchTerm, setSearchTerm] = useState('');
+
+  useEffect(() => {
+    getTenants().then(setTenants).catch(console.error);
+  }, []);
+
+  const handleEdit = (usuario: any) => {
+    setEditingUser({
+      id: usuario.id,
+      nombre: usuario.nombre,
+      role: usuario.role,
+      tenantId: usuario.tenantId,
+    });
+  };
+
+  const handleSave = async () => {
+    if (!editingUser) return;
+    try {
+      await updateUsuario.mutateAsync({
+        id: editingUser.id,
+        data: {
+          nombre: editingUser.nombre,
+          role: editingUser.role,
+          tenantId: editingUser.tenantId,
+        },
+      });
+      setEditingUser(null);
+    } catch (err: any) {
+      alert(err.response?.data?.error || 'Error al actualizar usuario');
+    }
+  };
+
+  const handleDelete = async (id: string) => {
+    if (!confirm('Estas seguro de eliminar este usuario?')) return;
+    try {
+      await deleteUsuario.mutateAsync(id);
+    } catch (err: any) {
+      alert(err.response?.data?.error || 'Error al eliminar usuario');
+    }
+  };
+
+  const filteredUsuarios = usuarios?.filter(u => {
+    const matchesTenant = filterTenant === 'all' || u.tenantId === filterTenant;
+    const matchesSearch = !searchTerm ||
+      u.nombre.toLowerCase().includes(searchTerm.toLowerCase()) ||
+      u.email.toLowerCase().includes(searchTerm.toLowerCase());
+    return matchesTenant && matchesSearch;
+  });
+
+  // Agrupar por empresa
+  const groupedByTenant = filteredUsuarios?.reduce((acc, u) => {
+    const key = u.tenantId || 'sin-empresa';
+    if (!acc[key]) {
+      acc[key] = {
+        tenantName: u.tenantName || 'Sin empresa',
+        users: [],
+      };
+    }
+    acc[key].users.push(u);
+    return acc;
+  }, {} as Record<string, { tenantName: string; users: typeof filteredUsuarios }>);
+
+  if (error) {
+    return (
+      <DashboardShell title="Administracion de Usuarios">
+        <Card>
+          <CardContent className="py-8 text-center">
+            <p className="text-destructive">
+              No tienes permisos para ver esta pagina o ocurrio un error.
+            </p>
+          </CardContent>
+        </Card>
+      </DashboardShell>
+    );
+  }
+
+  return (
+    <DashboardShell title="Administracion de Usuarios">
+      <div className="space-y-4">
+        {/* Filtros */}
+        <Card>
+          <CardContent className="py-4">
+            <div className="flex flex-wrap gap-4">
+              <div className="flex-1 min-w-[200px]">
+                <Input
+                  placeholder="Buscar por nombre o email..."
+                  value={searchTerm}
+                  onChange={(e) => setSearchTerm(e.target.value)}
+                />
+              </div>
+              <div className="w-[250px]">
+                <Select value={filterTenant} onValueChange={setFilterTenant}>
+                  <SelectTrigger>
+                    <SelectValue placeholder="Filtrar por empresa" />
+                  </SelectTrigger>
+                  <SelectContent>
+                    <SelectItem value="all">Todas las empresas</SelectItem>
+                    {tenants.map(t => (
+                      <SelectItem key={t.id} value={t.id}>{t.nombre}</SelectItem>
+                    ))}
+                  </SelectContent>
+                </Select>
+              </div>
+            </div>
+          </CardContent>
+        </Card>
+
+        {/* Stats */}
+        <div className="flex items-center gap-4">
+          <div className="flex items-center gap-2">
+            <Users className="h-5 w-5" />
+            <span className="font-medium">{filteredUsuarios?.length || 0} usuarios</span>
+          </div>
+          <div className="flex items-center gap-2 text-muted-foreground">
+            <Building2 className="h-4 w-4" />
+            <span className="text-sm">{Object.keys(groupedByTenant || {}).length} empresas</span>
+          </div>
+        </div>
+
+        {/* Users by tenant */}
+        {isLoading ? (
+          <Card>
+            <CardContent className="py-8 text-center text-muted-foreground">
+              Cargando usuarios...
+            </CardContent>
+          </Card>
+        ) : (
+          Object.entries(groupedByTenant || {}).map(([tenantId, { tenantName, users }]) => (
+            <Card key={tenantId}>
+              <CardHeader className="py-3">
+                <CardTitle className="text-base flex items-center gap-2">
+                  <Building2 className="h-4 w-4" />
+                  {tenantName}
+                  <span className="text-muted-foreground font-normal text-sm">
+                    ({users?.length} usuarios)
+                  </span>
+                </CardTitle>
+              </CardHeader>
+              <CardContent className="p-0">
+                <div className="divide-y">
+                  {users?.map(usuario => {
+                    const roleInfo = roleLabels[usuario.role];
+                    const RoleIcon = roleInfo.icon;
+                    const isCurrentUser = usuario.id === currentUser?.id;
+                    const isEditing = editingUser?.id === usuario.id;
+
+                    return (
+                      <div key={usuario.id} className="p-4 flex items-center justify-between">
+                        <div className="flex items-center gap-4 flex-1">
+                          <div className={cn(
+                            'w-10 h-10 rounded-full flex items-center justify-center',
+                            'bg-primary/10 text-primary font-medium'
+                          )}>
+                            {usuario.nombre.charAt(0).toUpperCase()}
+                          </div>
+                          <div className="flex-1">
+                            {isEditing ? (
+                              <div className="space-y-2">
+                                <Input
+                                  value={editingUser.nombre}
+                                  onChange={(e) => setEditingUser({ ...editingUser, nombre: e.target.value })}
+                                  className="h-8"
+                                />
+                                <div className="flex gap-2">
+                                  <Select
+                                    value={editingUser.role}
+                                    onValueChange={(v) => setEditingUser({ ...editingUser, role: v as any })}
+                                  >
+                                    <SelectTrigger className="h-8 w-[140px]">
+                                      <SelectValue />
+                                    </SelectTrigger>
+                                    <SelectContent>
+                                      <SelectItem value="admin">Administrador</SelectItem>
+                                      <SelectItem value="contador">Contador</SelectItem>
+                                      <SelectItem value="visor">Visor</SelectItem>
+                                    </SelectContent>
+                                  </Select>
+                                  <Select
+                                    value={editingUser.tenantId}
+                                    onValueChange={(v) => setEditingUser({ ...editingUser, tenantId: v })}
+                                  >
+                                    <SelectTrigger className="h-8 flex-1">
+                                      <SelectValue />
+                                    </SelectTrigger>
+                                    <SelectContent>
+                                      {tenants.map(t => (
+                                        <SelectItem key={t.id} value={t.id}>{t.nombre}</SelectItem>
+                                      ))}
+                                    </SelectContent>
+                                  </Select>
+                                </div>
+                              </div>
+                            ) : (
+                              <>
+                                <div className="flex items-center gap-2">
+                                  <span className="font-medium">{usuario.nombre}</span>
+                                  {isCurrentUser && (
+                                    <span className="text-xs bg-primary/10 text-primary px-2 py-0.5 rounded">Tu</span>
+                                  )}
+                                  {!usuario.active && (
+                                    <span className="text-xs bg-destructive/10 text-destructive px-2 py-0.5 rounded">Inactivo</span>
+                                  )}
+                                </div>
+                                <div className="text-sm text-muted-foreground">{usuario.email}</div>
+                              </>
+                            )}
+                          </div>
+                        </div>
+                        <div className="flex items-center gap-4">
+                          {!isEditing && (
+                            <div className={cn('flex items-center gap-1', roleInfo.color)}>
+                              <RoleIcon className="h-4 w-4" />
+                              <span className="text-sm">{roleInfo.label}</span>
+                            </div>
+                          )}
+                          {!isCurrentUser && (
+                            <div className="flex gap-1">
+                              {isEditing ? (
+                                <>
+                                  <Button
+                                    variant="ghost"
+                                    size="icon"
+                                    onClick={handleSave}
+                                    disabled={updateUsuario.isPending}
+                                  >
+                                    <Check className="h-4 w-4 text-green-600" />
+                                  </Button>
+                                  <Button
+                                    variant="ghost"
+                                    size="icon"
+                                    onClick={() => setEditingUser(null)}
+                                  >
+                                    <X className="h-4 w-4" />
+                                  </Button>
+                                </>
+                              ) : (
+                                <>
+                                  <Button
+                                    variant="ghost"
+                                    size="icon"
+                                    onClick={() => handleEdit(usuario)}
+                                  >
+                                    <Pencil className="h-4 w-4" />
+                                  </Button>
+                                  <Button
+                                    variant="ghost"
+                                    size="icon"
+                                    onClick={() => handleDelete(usuario.id)}
+                                  >
+                                    <Trash2 className="h-4 w-4 text-destructive" />
+                                  </Button>
+                                </>
+                              )}
+                            </div>
+                          )}
+                        </div>
+                      </div>
+                    );
+                  })}
+                </div>
+              </CardContent>
+            </Card>
+          ))
+        )}
+      </div>
+    </DashboardShell>
+  );
+}
diff --git a/apps/web/components/layouts/sidebar.tsx b/apps/web/components/layouts/sidebar.tsx
index d38a1a8..3f2e81f 100644
--- a/apps/web/components/layouts/sidebar.tsx
+++ b/apps/web/components/layouts/sidebar.tsx
@@ -15,6 +15,7 @@ import {
   Bell,
   Users,
   Building2,
+  UserCog,
 } from 'lucide-react';
 import { useAuthStore } from '@/stores/auth-store';
 import { logout } from '@/lib/api/auth';
@@ -33,6 +34,7 @@ const navigation = [
 
 const adminNavigation = [
   { name: 'Clientes', href: '/clientes', icon: Building2 },
+  { name: 'Admin Usuarios', href: '/admin/usuarios', icon: UserCog },
 ];
 
 export function Sidebar() {
diff --git a/apps/web/lib/api/usuarios.ts b/apps/web/lib/api/usuarios.ts
index 2c57985..c0c4442 100644
--- a/apps/web/lib/api/usuarios.ts
+++ b/apps/web/lib/api/usuarios.ts
@@ -19,3 +19,18 @@ export async function updateUsuario(id: string, data: UserUpdate): Promise<UserL
 export async function deleteUsuario(id: string): Promise<void> {
   await apiClient.delete(`/usuarios/${id}`);
 }
+
+// Funciones globales (admin global)
+export async function getAllUsuarios(): Promise<UserListItem[]> {
+  const response = await apiClient.get<UserListItem[]>('/usuarios/global/all');
+  return response.data;
+}
+
+export async function updateUsuarioGlobal(id: string, data: UserUpdate): Promise<UserListItem> {
+  const response = await apiClient.patch<UserListItem>(`/usuarios/global/${id}`, data);
+  return response.data;
+}
+
+export async function deleteUsuarioGlobal(id: string): Promise<void> {
+  await apiClient.delete(`/usuarios/global/${id}`);
+}
diff --git a/apps/web/lib/hooks/use-usuarios.ts b/apps/web/lib/hooks/use-usuarios.ts
index 31721dc..b3cc790 100644
--- a/apps/web/lib/hooks/use-usuarios.ts
+++ b/apps/web/lib/hooks/use-usuarios.ts
@@ -38,3 +38,31 @@ export function useDeleteUsuario() {
     },
   });
 }
+
+// Hooks globales (admin global)
+export function useAllUsuarios() {
+  return useQuery({
+    queryKey: ['usuarios', 'global'],
+    queryFn: usuariosApi.getAllUsuarios,
+  });
+}
+
+export function useUpdateUsuarioGlobal() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: ({ id, data }: { id: string; data: UserUpdate }) => usuariosApi.updateUsuarioGlobal(id, data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['usuarios'] });
+    },
+  });
+}
+
+export function useDeleteUsuarioGlobal() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: (id: string) => usuariosApi.deleteUsuarioGlobal(id),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['usuarios'] });
+    },
+  });
+}
diff --git a/packages/shared/src/types/user.ts b/packages/shared/src/types/user.ts
index e5f6fae..e5e90b3 100644
--- a/packages/shared/src/types/user.ts
+++ b/packages/shared/src/types/user.ts
@@ -38,12 +38,15 @@ export interface UserListItem {
   active: boolean;
   lastLogin: string | null;
   createdAt: string;
+  tenantId?: string;
+  tenantName?: string;
 }
 
 export interface UserUpdate {
   nombre?: string;
   role?: 'admin' | 'contador' | 'visor';
   active?: boolean;
+  tenantId?: string;
 }
 
 export interface AuditLog {