diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index b4119305f99..183caa898ef 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -1358,7 +1358,6 @@ def test_open_default_encoding(self):
             os.environ.clear()
             os.environ.update(old_environ)
 
-    @unittest.expectedFailureIfWindows('TODO: RUSTPYTHON Windows')
     @support.requires_subprocess()
     def test_open_non_inheritable(self):
         fileobj = open(__file__, encoding="utf-8")
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index c86d910eef6..6f111b2ffcd 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -2102,7 +2102,6 @@ def test_urandom_failure(self):
             """
         assert_python_ok('-c', code)
 
-    @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON; on Windows (ModuleNotFoundError: No module named 'os')")
     def test_urandom_fd_closed(self):
         # Issue #21207: urandom() should reopen its fd to /dev/urandom if
         # closed.
@@ -4621,7 +4620,6 @@ def test_process_cpu_count_affinity(self):
 # FD inheritance check is only useful for systems with process support.
 @support.requires_subprocess()
 class FDInheritanceTests(unittest.TestCase):
-    @unittest.expectedFailureIfWindows('TODO: RUSTPYTHON; os.get_inheritable not implemented yet for all platforms')
     def test_get_set_inheritable(self):
         fd = os.open(__file__, os.O_RDONLY)
         self.addCleanup(os.close, fd)
@@ -4682,7 +4680,6 @@ def test_get_set_inheritable_badf(self):
             os.set_inheritable(fd, False)
         self.assertEqual(ctx.exception.errno, errno.EBADF)
 
-    @unittest.expectedFailureIfWindows('TODO: RUSTPYTHON; os.get_inheritable not implemented yet for all platforms')
     def test_open(self):
         fd = os.open(__file__, os.O_RDONLY)
         self.addCleanup(os.close, fd)
@@ -4696,7 +4693,6 @@ def test_pipe(self):
         self.assertEqual(os.get_inheritable(rfd), False)
         self.assertEqual(os.get_inheritable(wfd), False)
 
-    @unittest.skipIf(sys.platform == 'win32', 'TODO: RUSTPYTHON; os.dup on windows')
     def test_dup(self):
         fd1 = os.open(__file__, os.O_RDONLY)
         self.addCleanup(os.close, fd1)
@@ -4705,13 +4701,11 @@ def test_dup(self):
         self.addCleanup(os.close, fd2)
         self.assertEqual(os.get_inheritable(fd2), False)
 
-    @unittest.skipIf(sys.platform == 'win32', 'TODO: RUSTPYTHON; os.dup on windows')
     def test_dup_standard_stream(self):
         fd = os.dup(1)
         self.addCleanup(os.close, fd)
         self.assertGreater(fd, 0)
 
-    @unittest.expectedFailureIfWindows('TODO: RUSTPYTHON; os.dup not implemented yet for all platforms')
     @unittest.skipUnless(sys.platform == 'win32', 'win32-specific test')
     def test_dup_nul(self):
         # os.dup() was creating inheritable fds for character files.
diff --git a/crates/vm/src/stdlib/nt.rs b/crates/vm/src/stdlib/nt.rs
index e2d4b41cc3c..0464fa42f30 100644
--- a/crates/vm/src/stdlib/nt.rs
+++ b/crates/vm/src/stdlib/nt.rs
@@ -14,7 +14,7 @@ pub(crate) fn make_module(vm: &VirtualMachine) -> PyRef<PyModule> {
 pub(crate) mod module {
     use crate::{
         PyResult, TryFromObject, VirtualMachine,
-        builtins::{PyDictRef, PyListRef, PyStrRef, PyTupleRef},
+        builtins::{PyBaseExceptionRef, PyDictRef, PyListRef, PyStrRef, PyTupleRef},
         common::{crt_fd, os::last_os_error, suppress_iph},
         convert::ToPyException,
         function::{Either, OptionalArg},
@@ -391,6 +391,13 @@ pub(crate) mod module {
         }
     }
 
+    #[pyfunction]
+    fn get_inheritable(fd: i32, vm: &VirtualMachine) -> PyResult<bool> {
+        let borrowed = unsafe { crt_fd::Borrowed::borrow_raw(fd) };
+        let handle = crt_fd::as_handle(borrowed).map_err(|e| e.to_pyexception(vm))?;
+        get_handle_inheritable(handle.as_raw_handle() as _, vm)
+    }
+
     #[pyfunction]
     fn getlogin(vm: &VirtualMachine) -> PyResult<String> {
         let mut buffer = [0u16; 257];
@@ -477,6 +484,15 @@ pub(crate) mod module {
 
     unsafe extern "C" {
         fn _umask(mask: i32) -> i32;
+        fn _dup(fd: i32) -> i32;
+        fn _dup2(fd: i32, fd2: i32) -> i32;
+    }
+
+    /// Close fd and convert error to PyException (PEP 446 cleanup)
+    #[cold]
+    fn close_fd_and_raise(fd: i32, err: std::io::Error, vm: &VirtualMachine) -> PyBaseExceptionRef {
+        let _ = unsafe { crt_fd::Owned::from_raw(fd) };
+        err.to_pyexception(vm)
     }
 
     #[pyfunction]
@@ -489,6 +505,45 @@ pub(crate) mod module {
         }
     }
 
+    #[pyfunction]
+    fn dup(fd: i32, vm: &VirtualMachine) -> PyResult<i32> {
+        let fd2 = unsafe { suppress_iph!(_dup(fd)) };
+        if fd2 < 0 {
+            return Err(errno_err(vm));
+        }
+        let borrowed = unsafe { crt_fd::Borrowed::borrow_raw(fd2) };
+        let handle = crt_fd::as_handle(borrowed).map_err(|e| close_fd_and_raise(fd2, e, vm))?;
+        raw_set_handle_inheritable(handle.as_raw_handle() as _, false)
+            .map_err(|e| close_fd_and_raise(fd2, e, vm))?;
+        Ok(fd2)
+    }
+
+    #[derive(FromArgs)]
+    struct Dup2Args {
+        #[pyarg(positional)]
+        fd: i32,
+        #[pyarg(positional)]
+        fd2: i32,
+        #[pyarg(any, default = true)]
+        inheritable: bool,
+    }
+
+    #[pyfunction]
+    fn dup2(args: Dup2Args, vm: &VirtualMachine) -> PyResult<i32> {
+        let result = unsafe { suppress_iph!(_dup2(args.fd, args.fd2)) };
+        if result < 0 {
+            return Err(errno_err(vm));
+        }
+        if !args.inheritable {
+            let borrowed = unsafe { crt_fd::Borrowed::borrow_raw(args.fd2) };
+            let handle =
+                crt_fd::as_handle(borrowed).map_err(|e| close_fd_and_raise(args.fd2, e, vm))?;
+            raw_set_handle_inheritable(handle.as_raw_handle() as _, false)
+                .map_err(|e| close_fd_and_raise(args.fd2, e, vm))?;
+        }
+        Ok(args.fd2)
+    }
+
     pub(crate) fn support_funcs() -> Vec<SupportFunc> {
         Vec::new()
     }