diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5e72afc..6f3f8be 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -102,6 +102,11 @@
 set(PYBIND11_INTERNALS_VERSION
     ""
     CACHE STRING "Override the ABI version, may be used to enable the unstable ABI.")
+# Record whether the project set this before option() supplies its OFF default, so
+# pybind11Common.cmake can apply its CMP0190-aware default without clobbering an explicit value.
+if(NOT DEFINED PYBIND11_USE_CROSSCOMPILING)
+  set(_PYBIND11_USE_CROSSCOMPILING_DEFAULTED ON)
+endif()
 option(PYBIND11_USE_CROSSCOMPILING "Respect CMAKE_CROSSCOMPILING" OFF)
 
 if(PYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION)
diff --git a/tools/pybind11Common.cmake b/tools/pybind11Common.cmake
index f525270..d75fb67 100644
--- a/tools/pybind11Common.cmake
+++ b/tools/pybind11Common.cmake
@@ -43,16 +43,21 @@
 
 # CMP0190 prohibits calling FindPython with both Interpreter and Development components
 # when cross-compiling, unless the CMAKE_CROSSCOMPILING_EMULATOR variable is defined.
-if(CMAKE_VERSION VERSION_GREATER_EQUAL "4.1")
+# Default PYBIND11_USE_CROSSCOMPILING to ON in that case, but never override a value the
+# project set explicitly (e.g. Emscripten/Pyodide defines an emulator yet still wants it ON).
+# PYBIND11_USE_CROSSCOMPILING is undefined for find_package() consumers, but our own
+# CMakeLists.txt always defines it via option(); _PYBIND11_USE_CROSSCOMPILING_DEFAULTED tells
+# us whether that came from the project or from the option() default.
+if(CMAKE_VERSION VERSION_GREATER_EQUAL "4.1"
+   AND NOT DEFINED CMAKE_CROSSCOMPILING_EMULATOR
+   AND (NOT DEFINED PYBIND11_USE_CROSSCOMPILING OR _PYBIND11_USE_CROSSCOMPILING_DEFAULTED))
   cmake_policy(GET CMP0190 _pybind11_cmp0190)
   if(_pybind11_cmp0190 STREQUAL "NEW")
     set(PYBIND11_USE_CROSSCOMPILING "ON")
   endif()
 endif()
 
-if(CMAKE_CROSSCOMPILING
-   AND PYBIND11_USE_CROSSCOMPILING
-   AND NOT DEFINED CMAKE_CROSSCOMPILING_EMULATOR)
+if(CMAKE_CROSSCOMPILING AND PYBIND11_USE_CROSSCOMPILING)
   set(_PYBIND11_CROSSCOMPILING
       ON
       CACHE INTERNAL "")