diff --git a/include/pybind11/attr.h b/include/pybind11/attr.h
index 44a33458..54760cdb 100644
--- a/include/pybind11/attr.h
+++ b/include/pybind11/attr.h
@@ -12,7 +12,7 @@
 
 #include "cast.h"
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 /// \addtogroup annotations
 /// @{
@@ -478,4 +478,4 @@ constexpr bool expected_num_args(size_t nargs, bool has_args, bool has_kwargs) {
 }
 
 NAMESPACE_END(detail)
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/buffer_info.h b/include/pybind11/buffer_info.h
index 6d1167d2..1f5e3a95 100644
--- a/include/pybind11/buffer_info.h
+++ b/include/pybind11/buffer_info.h
@@ -11,7 +11,7 @@
 
 #include "common.h"
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 /// Information record describing a Python buffer object
 struct buffer_info {
@@ -105,4 +105,4 @@ template <typename T> struct compare_buffer_info<T, detail::enable_if_t<std::is_
 };
 
 NAMESPACE_END(detail)
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
index cfd565e5..41e65cc8 100644
--- a/include/pybind11/cast.h
+++ b/include/pybind11/cast.h
@@ -30,7 +30,7 @@
 #include <string_view>
 #endif
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 // Forward declarations:
 inline PyTypeObject *make_static_property_type();
@@ -2084,4 +2084,4 @@ NAMESPACE_END(detail)
         template<> class type_caster<Type> : public type_caster_base<Type> { }; \
     }}
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/chrono.h b/include/pybind11/chrono.h
index 8a41d08b..95ada76e 100644
--- a/include/pybind11/chrono.h
+++ b/include/pybind11/chrono.h
@@ -27,7 +27,7 @@
 #define PyDateTime_DELTA_GET_MICROSECONDS(o) (((PyDateTime_Delta*)o)->microseconds)
 #endif
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 
 template <typename type> class duration_caster {
@@ -159,4 +159,4 @@ template <typename Rep, typename Period> class type_caster<std::chrono::duration
 };
 
 NAMESPACE_END(detail)
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/class_support.h b/include/pybind11/class_support.h
index 287412d9..d006a1e5 100644
--- a/include/pybind11/class_support.h
+++ b/include/pybind11/class_support.h
@@ -11,7 +11,7 @@
 
 #include "attr.h"
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 
 inline PyTypeObject *type_incref(PyTypeObject *type) {
@@ -599,4 +599,4 @@ inline PyObject* make_new_python_type(const type_record &rec) {
 }
 
 NAMESPACE_END(detail)
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/common.h b/include/pybind11/common.h
index dc50b7cf..e83a6475 100644
--- a/include/pybind11/common.h
+++ b/include/pybind11/common.h
@@ -16,6 +16,17 @@
 #  define NAMESPACE_END(name) }
 #endif
 
+// Robust support for some features and loading modules compiled against different pybind versions
+// requires forcing hidden visibility on pybind code, so we enforce this by setting the attribute on
+// the main `pybind11` namespace.
+#if !defined(PYBIND11_NAMESPACE)
+#  ifdef __GNUG__
+#    define PYBIND11_NAMESPACE pybind11 __attribute__((visibility("hidden")))
+#  else
+#    define PYBIND11_NAMESPACE pybind11
+#  endif
+#endif
+
 #if !defined(_MSC_VER) && !defined(__INTEL_COMPILER)
 #  if __cplusplus >= 201402L
 #    define PYBIND11_CPP14
@@ -297,7 +308,7 @@ extern "C" {
     void pybind11_init_##name(pybind11::module &variable)
 
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 using ssize_t = Py_ssize_t;
 using size_t  = std::size_t;
@@ -877,4 +888,4 @@ NAMESPACE_END(detail)
 
 
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/complex.h b/include/pybind11/complex.h
index 7d422e20..5dac27cc 100644
--- a/include/pybind11/complex.h
+++ b/include/pybind11/complex.h
@@ -17,7 +17,7 @@
 #  undef I
 #endif
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 template <typename T> struct format_descriptor<std::complex<T>, detail::enable_if_t<std::is_floating_point<T>::value>> {
     static constexpr const char c = format_descriptor<T>::c;
@@ -58,4 +58,4 @@ public:
     PYBIND11_TYPE_CASTER(std::complex<T>, _("complex"));
 };
 NAMESPACE_END(detail)
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/descr.h b/include/pybind11/descr.h
index 23a099cf..f6c0a683 100644
--- a/include/pybind11/descr.h
+++ b/include/pybind11/descr.h
@@ -12,7 +12,7 @@
 
 #include "common.h"
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 
 /* Concatenate type signatures at compile time using C++14 */
@@ -182,4 +182,4 @@ PYBIND11_NOINLINE inline descr type_descr(descr&& d) { return _("{") + std::move
 #endif
 
 NAMESPACE_END(detail)
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/eigen.h b/include/pybind11/eigen.h
index fc070516..a702bf39 100644
--- a/include/pybind11/eigen.h
+++ b/include/pybind11/eigen.h
@@ -35,7 +35,7 @@
 // of matrices seems highly undesirable.
 static_assert(EIGEN_VERSION_AT_LEAST(3,2,7), "Eigen support in pybind11 requires Eigen >= 3.2.7");
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 // Provide a convenience alias for easier pass-by-ref usage with fully dynamic strides:
 using EigenDStride = Eigen::Stride<Eigen::Dynamic, Eigen::Dynamic>;
@@ -601,7 +601,7 @@ struct type_caster<Type, enable_if_t<is_eigen_sparse<Type>::value>> {
 };
 
 NAMESPACE_END(detail)
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
 
 #if defined(__GNUG__) || defined(__clang__)
 #  pragma GCC diagnostic pop
diff --git a/include/pybind11/embed.h b/include/pybind11/embed.h
index 98bf7690..79ad0209 100644
--- a/include/pybind11/embed.h
+++ b/include/pybind11/embed.h
@@ -63,7 +63,7 @@
     void pybind11_init_##name(pybind11::module &variable)
 
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 
 /// Python 2.7/3.x compatible version of `PyImport_AppendInittab` and error checks.
@@ -190,4 +190,4 @@ private:
     bool is_valid = true;
 };
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/eval.h b/include/pybind11/eval.h
index 165003b8..ea85ba1d 100644
--- a/include/pybind11/eval.h
+++ b/include/pybind11/eval.h
@@ -13,7 +13,7 @@
 
 #include "pybind11.h"
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 enum eval_mode {
     /// Evaluate a string containing an isolated expression
@@ -114,4 +114,4 @@ object eval_file(str fname, object global = globals(), object local = object())
     return reinterpret_steal<object>(result);
 }
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/functional.h b/include/pybind11/functional.h
index fdb6b330..eda14ba5 100644
--- a/include/pybind11/functional.h
+++ b/include/pybind11/functional.h
@@ -12,7 +12,7 @@
 #include "pybind11.h"
 #include <functional>
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 
 template <typename Return, typename... Args>
@@ -82,4 +82,4 @@ public:
 };
 
 NAMESPACE_END(detail)
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/numpy.h b/include/pybind11/numpy.h
index 57d44214..4ee25619 100644
--- a/include/pybind11/numpy.h
+++ b/include/pybind11/numpy.h
@@ -34,7 +34,7 @@
    upon the library user. */
 static_assert(sizeof(ssize_t) == sizeof(Py_intptr_t), "ssize_t != Py_intptr_t");
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 class array; // Forward declaration
 
@@ -1591,7 +1591,7 @@ Helper vectorize(Return (Class::*f)(Args...) const) {
     return Helper(std::mem_fn(f));
 }
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
 
 #if defined(_MSC_VER)
 #pragma warning(pop)
diff --git a/include/pybind11/operators.h b/include/pybind11/operators.h
index 562987b8..11ea2485 100644
--- a/include/pybind11/operators.h
+++ b/include/pybind11/operators.h
@@ -18,7 +18,7 @@
 #  pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
 #endif
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 
 /// Enumeration with all supported operator types
@@ -160,7 +160,7 @@ NAMESPACE_END(detail)
 
 using detail::self;
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
 
 #if defined(_MSC_VER)
 #  pragma warning(pop)
diff --git a/include/pybind11/options.h b/include/pybind11/options.h
index 3105551d..531ec8a8 100644
--- a/include/pybind11/options.h
+++ b/include/pybind11/options.h
@@ -11,7 +11,7 @@
 
 #include "common.h"
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 class options {
 public:
@@ -62,4 +62,4 @@ private:
     state previous_state;
 };
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/pybind11.h b/include/pybind11/pybind11.h
index 2e697016..01c02dc4 100644
--- a/include/pybind11/pybind11.h
+++ b/include/pybind11/pybind11.h
@@ -44,7 +44,7 @@
 #include "options.h"
 #include "class_support.h"
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 /// Wraps an arbitrary C++ function/method/lambda function/.. into a callable Python object
 class cpp_function : public function {
@@ -1862,7 +1862,7 @@ template <class T> function get_overload(const T *this_ptr, const char *name) {
 #define PYBIND11_OVERLOAD_PURE(ret_type, cname, fn, ...) \
     PYBIND11_OVERLOAD_PURE_NAME(ret_type, cname, #fn, fn, __VA_ARGS__)
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
 
 #if defined(_MSC_VER)
 #  pragma warning(pop)
diff --git a/include/pybind11/pytypes.h b/include/pybind11/pytypes.h
index b652b8e9..ba30e84e 100644
--- a/include/pybind11/pytypes.h
+++ b/include/pybind11/pytypes.h
@@ -14,7 +14,7 @@
 #include <utility>
 #include <type_traits>
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 /* A few forward declarations */
 class handle; class object;
@@ -1320,4 +1320,4 @@ template <typename D>
 handle object_api<D>::get_type() const { return (PyObject *) Py_TYPE(derived().ptr()); }
 
 NAMESPACE_END(detail)
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/stl.h b/include/pybind11/stl.h
index c8c9e906..ac212bfe 100644
--- a/include/pybind11/stl.h
+++ b/include/pybind11/stl.h
@@ -46,7 +46,7 @@
 #  define PYBIND11_HAS_VARIANT 1
 #endif
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 
 /// Extracts an const lvalue reference or rvalue reference for U based on the type of T (e.g. for
@@ -362,7 +362,7 @@ inline std::ostream &operator<<(std::ostream &os, const handle &obj) {
     return os;
 }
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
 
 #if defined(_MSC_VER)
 #pragma warning(pop)
diff --git a/include/pybind11/stl_bind.h b/include/pybind11/stl_bind.h
index 6263f992..d9f5b56d 100644
--- a/include/pybind11/stl_bind.h
+++ b/include/pybind11/stl_bind.h
@@ -15,7 +15,7 @@
 #include <algorithm>
 #include <sstream>
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 
 /* SFINAE helper class used by 'is_comparable */
@@ -598,4 +598,4 @@ class_<Map, holder_type> bind_map(handle scope, const std::string &name, Args&&.
     return cl;
 }
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/include/pybind11/typeid.h b/include/pybind11/typeid.h
index c903fb14..9d3ddcd5 100644
--- a/include/pybind11/typeid.h
+++ b/include/pybind11/typeid.h
@@ -16,7 +16,7 @@
 #include <cxxabi.h>
 #endif
 
-NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 /// Erase all occurrences of a substring
 inline void erase_all(std::string &string, const std::string &search) {
@@ -50,4 +50,4 @@ template <typename T> static std::string type_id() {
     return name;
 }
 
-NAMESPACE_END(pybind11)
+NAMESPACE_END(PYBIND11_NAMESPACE)