diff --git a/.codespell-ignore-lines b/.codespell-ignore-lines
index 3ed39dfab..0c622ff58 100644
--- a/.codespell-ignore-lines
+++ b/.codespell-ignore-lines
@@ -20,6 +20,8 @@ template <op_id id, op_type ot, typename L, typename R>
         REQUIRE(othr.valu == 19);
         REQUIRE(orig.valu == 91);
         (m.pass_valu, "Valu", "pass_valu:Valu(_MvCtor)*_CpCtor"),
+atyp_valu        rtrn_valu() { atyp_valu obj{"Valu"}; return obj; }
+    assert m.atyp_valu().get_mtxt() == "Valu"
 @pytest.mark.parametrize("access", ["ro", "rw", "static_ro", "static_rw"])
 struct IntStruct {
     explicit IntStruct(int v) : value(v){};
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 24bd3905b..70bff59cb 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -120,6 +120,7 @@ set(PYBIND11_TEST_FILES
     test_chrono
     test_class
     test_class_sh_basic
+    test_class_sh_factory_constructors
     test_const_name
     test_constants_and_functions
     test_copy_move
diff --git a/tests/test_class_sh_factory_constructors.cpp b/tests/test_class_sh_factory_constructors.cpp
new file mode 100644
index 000000000..937672cbd
--- /dev/null
+++ b/tests/test_class_sh_factory_constructors.cpp
@@ -0,0 +1,180 @@
+#include <pybind11/smart_holder.h>
+
+#include "pybind11_tests.h"
+
+#include <memory>
+#include <string>
+
+namespace pybind11_tests {
+namespace class_sh_factory_constructors {
+
+template <int> // Using int as a trick to easily generate a series of types.
+struct atyp {  // Short for "any type".
+    std::string mtxt;
+};
+
+template <typename T>
+std::string get_mtxt(const T &obj) {
+    return obj.mtxt;
+}
+
+using atyp_valu = atyp<0x0>;
+using atyp_rref = atyp<0x1>;
+using atyp_cref = atyp<0x2>;
+using atyp_mref = atyp<0x3>;
+using atyp_cptr = atyp<0x4>;
+using atyp_mptr = atyp<0x5>;
+using atyp_shmp = atyp<0x6>;
+using atyp_shcp = atyp<0x7>;
+using atyp_uqmp = atyp<0x8>;
+using atyp_uqcp = atyp<0x9>;
+using atyp_udmp = atyp<0xA>;
+using atyp_udcp = atyp<0xB>;
+
+// clang-format off
+
+atyp_valu        rtrn_valu() { atyp_valu obj{"Valu"}; return obj; }
+atyp_rref&&      rtrn_rref() { static atyp_rref obj; obj.mtxt = "Rref"; return std::move(obj); }
+atyp_cref const& rtrn_cref() { static atyp_cref obj; obj.mtxt = "Cref"; return obj; }
+atyp_mref&       rtrn_mref() { static atyp_mref obj; obj.mtxt = "Mref"; return obj; }
+atyp_cptr const* rtrn_cptr() { return new atyp_cptr{"Cptr"}; }
+atyp_mptr*       rtrn_mptr() { return new atyp_mptr{"Mptr"}; }
+
+std::shared_ptr<atyp_shmp>       rtrn_shmp() { return std::make_shared<atyp_shmp>(atyp_shmp{"Shmp"}); }
+std::shared_ptr<atyp_shcp const> rtrn_shcp() { return std::shared_ptr<atyp_shcp const>(new atyp_shcp{"Shcp"}); }
+
+std::unique_ptr<atyp_uqmp>       rtrn_uqmp() { return std::unique_ptr<atyp_uqmp      >(new atyp_uqmp{"Uqmp"}); }
+std::unique_ptr<atyp_uqcp const> rtrn_uqcp() { return std::unique_ptr<atyp_uqcp const>(new atyp_uqcp{"Uqcp"}); }
+
+struct sddm : std::default_delete<atyp_udmp      > {};
+struct sddc : std::default_delete<atyp_udcp const> {};
+
+std::unique_ptr<atyp_udmp,       sddm> rtrn_udmp() { return std::unique_ptr<atyp_udmp,       sddm>(new atyp_udmp{"Udmp"}); }
+std::unique_ptr<atyp_udcp const, sddc> rtrn_udcp() { return std::unique_ptr<atyp_udcp const, sddc>(new atyp_udcp{"Udcp"}); }
+
+// clang-format on
+
+// Minimalistic approach to achieve full coverage of construct() overloads for constructing
+// smart_holder from unique_ptr and shared_ptr returns.
+struct with_alias {
+    int val = 0;
+    virtual ~with_alias() = default;
+    // Some compilers complain about implicitly defined versions of some of the following:
+    with_alias() = default;
+    with_alias(const with_alias &) = default;
+    with_alias(with_alias &&) = default;
+    with_alias &operator=(const with_alias &) = default;
+    with_alias &operator=(with_alias &&) = default;
+};
+struct with_alias_alias : with_alias {};
+struct sddwaa : std::default_delete<with_alias_alias> {};
+
+} // namespace class_sh_factory_constructors
+} // namespace pybind11_tests
+
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_valu)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_rref)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_cref)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_mref)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_cptr)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_mptr)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_shmp)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_shcp)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_uqmp)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_uqcp)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_udmp)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::atyp_udcp)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_factory_constructors::with_alias)
+
+TEST_SUBMODULE(class_sh_factory_constructors, m) {
+    using namespace pybind11_tests::class_sh_factory_constructors;
+
+    py::classh<atyp_valu>(m, "atyp_valu")
+        .def(py::init(&rtrn_valu))
+        .def("get_mtxt", get_mtxt<atyp_valu>);
+
+    py::classh<atyp_rref>(m, "atyp_rref")
+        .def(py::init(&rtrn_rref))
+        .def("get_mtxt", get_mtxt<atyp_rref>);
+
+    py::classh<atyp_cref>(m, "atyp_cref")
+        // class_: ... must return a compatible ...
+        // classh: ... cannot pass object of non-trivial type ...
+        // .def(py::init(&rtrn_cref))
+        .def("get_mtxt", get_mtxt<atyp_cref>);
+
+    py::classh<atyp_mref>(m, "atyp_mref")
+        // class_: ... must return a compatible ...
+        // classh: ... cannot pass object of non-trivial type ...
+        // .def(py::init(&rtrn_mref))
+        .def("get_mtxt", get_mtxt<atyp_mref>);
+
+    py::classh<atyp_cptr>(m, "atyp_cptr")
+        // class_: ... must return a compatible ...
+        // classh: ... must return a compatible ...
+        // .def(py::init(&rtrn_cptr))
+        .def("get_mtxt", get_mtxt<atyp_cptr>);
+
+    py::classh<atyp_mptr>(m, "atyp_mptr")
+        .def(py::init(&rtrn_mptr))
+        .def("get_mtxt", get_mtxt<atyp_mptr>);
+
+    py::classh<atyp_shmp>(m, "atyp_shmp")
+        .def(py::init(&rtrn_shmp))
+        .def("get_mtxt", get_mtxt<atyp_shmp>);
+
+    py::classh<atyp_shcp>(m, "atyp_shcp")
+        // py::class_<atyp_shcp, std::shared_ptr<atyp_shcp>>(m, "atyp_shcp")
+        // class_: ... must return a compatible ...
+        // classh: ... cannot pass object of non-trivial type ...
+        // .def(py::init(&rtrn_shcp))
+        .def("get_mtxt", get_mtxt<atyp_shcp>);
+
+    py::classh<atyp_uqmp>(m, "atyp_uqmp")
+        .def(py::init(&rtrn_uqmp))
+        .def("get_mtxt", get_mtxt<atyp_uqmp>);
+
+    py::classh<atyp_uqcp>(m, "atyp_uqcp")
+        // class_: ... cannot pass object of non-trivial type ...
+        // classh: ... cannot pass object of non-trivial type ...
+        // .def(py::init(&rtrn_uqcp))
+        .def("get_mtxt", get_mtxt<atyp_uqcp>);
+
+    py::classh<atyp_udmp>(m, "atyp_udmp")
+        .def(py::init(&rtrn_udmp))
+        .def("get_mtxt", get_mtxt<atyp_udmp>);
+
+    py::classh<atyp_udcp>(m, "atyp_udcp")
+        // py::class_<atyp_udcp, std::unique_ptr<atyp_udcp, sddc>>(m, "atyp_udcp")
+        // class_: ... must return a compatible ...
+        // classh: ... cannot pass object of non-trivial type ...
+        // .def(py::init(&rtrn_udcp))
+        .def("get_mtxt", get_mtxt<atyp_udcp>);
+
+    py::classh<with_alias, with_alias_alias>(m, "with_alias")
+        .def_readonly("val", &with_alias::val)
+        .def(py::init([](int i) {
+            auto p = std::unique_ptr<with_alias_alias, sddwaa>(new with_alias_alias);
+            p->val = i * 100;
+            return p;
+        }))
+        .def(py::init([](int i, int j) {
+            auto p = std::unique_ptr<with_alias_alias>(new with_alias_alias);
+            p->val = i * 100 + j * 10;
+            return p;
+        }))
+        .def(py::init([](int i, int j, int k) {
+            auto p = std::make_shared<with_alias_alias>();
+            p->val = i * 100 + j * 10 + k;
+            return p;
+        }))
+        .def(py::init(
+            [](int, int, int, int) { return std::unique_ptr<with_alias>(new with_alias); },
+            [](int, int, int, int) {
+                return std::unique_ptr<with_alias>(new with_alias); // Invalid alias factory.
+            }))
+        .def(py::init([](int, int, int, int, int) { return std::make_shared<with_alias>(); },
+                      [](int, int, int, int, int) {
+                          return std::make_shared<with_alias>(); // Invalid alias factory.
+                      }));
+}
diff --git a/tests/test_class_sh_factory_constructors.py b/tests/test_class_sh_factory_constructors.py
new file mode 100644
index 000000000..5d45db6fd
--- /dev/null
+++ b/tests/test_class_sh_factory_constructors.py
@@ -0,0 +1,53 @@
+from __future__ import annotations
+
+import pytest
+
+from pybind11_tests import class_sh_factory_constructors as m
+
+
+def test_atyp_factories():
+    assert m.atyp_valu().get_mtxt() == "Valu"
+    assert m.atyp_rref().get_mtxt() == "Rref"
+    # sert m.atyp_cref().get_mtxt() == "Cref"
+    # sert m.atyp_mref().get_mtxt() == "Mref"
+    # sert m.atyp_cptr().get_mtxt() == "Cptr"
+    assert m.atyp_mptr().get_mtxt() == "Mptr"
+    assert m.atyp_shmp().get_mtxt() == "Shmp"
+    # sert m.atyp_shcp().get_mtxt() == "Shcp"
+    assert m.atyp_uqmp().get_mtxt() == "Uqmp"
+    # sert m.atyp_uqcp().get_mtxt() == "Uqcp"
+    assert m.atyp_udmp().get_mtxt() == "Udmp"
+    # sert m.atyp_udcp().get_mtxt() == "Udcp"
+
+
+@pytest.mark.parametrize(
+    ("init_args", "expected"),
+    [
+        ((3,), 300),
+        ((5, 7), 570),
+        ((9, 11, 13), 1023),
+    ],
+)
+def test_with_alias_success(init_args, expected):
+    assert m.with_alias(*init_args).val == expected
+
+
+@pytest.mark.parametrize(
+    ("num_init_args", "smart_ptr"),
+    [
+        (4, "std::unique_ptr"),
+        (5, "std::shared_ptr"),
+    ],
+)
+def test_with_alias_invalid(num_init_args, smart_ptr):
+    class PyDrvdWithAlias(m.with_alias):
+        pass
+
+    with pytest.raises(TypeError) as excinfo:
+        PyDrvdWithAlias(*((0,) * num_init_args))
+    assert (
+        str(excinfo.value)
+        == "pybind11::init(): construction failed: returned "
+        + smart_ptr
+        + " pointee is not an alias instance"
+    )