diff --git a/CMakeLists.txt b/CMakeLists.txt
index dd66ce5b45a..dd146ef57c8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,6 +16,9 @@ cmake_minimum_required(VERSION 3.25)
 
 project(Vortex DESCRIPTION "Vortex C and C++ libraries" LANGUAGES NONE)
 
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
 # Directory-scoped developer defaults; an embedded root resets inherited ownership.
 set(_vortex_top_level "${PROJECT_IS_TOP_LEVEL}")
 
diff --git a/lang/cpp/CMakeLists.txt b/lang/cpp/CMakeLists.txt
index 7884228cf70..47d977697df 100644
--- a/lang/cpp/CMakeLists.txt
+++ b/lang/cpp/CMakeLists.txt
@@ -10,6 +10,9 @@ cmake_minimum_required(VERSION 3.25)
 
 project(VortexCXX DESCRIPTION "Vortex C++ wrapper" LANGUAGES C CXX)
 
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
 # Standalone entry points own their defaults; otherwise inherit Vortex's marker.
 if(PROJECT_IS_TOP_LEVEL)
     set(_vortex_top_level ON)
diff --git a/vortex-ffi/CMakeLists.txt b/vortex-ffi/CMakeLists.txt
index a7d891e447e..8e2db94db14 100644
--- a/vortex-ffi/CMakeLists.txt
+++ b/vortex-ffi/CMakeLists.txt
@@ -10,6 +10,9 @@ cmake_minimum_required(VERSION 3.25)
 
 project(VortexFFI DESCRIPTION "Vortex C FFI" LANGUAGES C CXX)
 
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
 # Standalone entry points own their defaults; otherwise inherit Vortex's marker.
 if(PROJECT_IS_TOP_LEVEL)
     set(_vortex_top_level ON)