diff --git a/platforms/posix/src/px4/windows/tests/test_windows_shim_poll.cpp b/platforms/posix/src/px4/windows/tests/test_windows_shim_poll.cpp
new file mode 100644
index 0000000000..9ddce2d0ce
--- /dev/null
+++ b/platforms/posix/src/px4/windows/tests/test_windows_shim_poll.cpp
@@ -0,0 +1,417 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2026 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file test_windows_shim_poll.cpp
+ *
+ * Unit tests for the inline poll() implementation in
+ * platforms/posix/include/windows_shim/poll.h. The shim classifies fd
+ * kinds (socket / pipe / char / disk / invalid), routes pure-socket
+ * calls through WSAPoll, and otherwise mixes manual readiness probes
+ * with a tight WSAPoll fallback for the socket subset.
+ *
+ * Each branch is exercised: argument validation, socket loopback, pipe
+ * with and without pending data, disk-fd always-ready, ignored fd, and
+ * the timeout/timeout=0 fast paths.
+ */
+
+#include <gtest/gtest.h>
+
+#ifdef _WIN32
+
+#define _WIN32_WINNT 0x0A00
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#include <windows.h>
+#include <io.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <chrono>
+
+#include <poll.h>
+
+namespace
+{
+class WinsockBootstrap
+{
+public:
+	WinsockBootstrap()
+	{
+		WSADATA wsa;
+		WSAStartup(MAKEWORD(2, 2), &wsa);
+	}
+
+	~WinsockBootstrap()
+	{
+		WSACleanup();
+	}
+};
+
+/* Lightweight UDP loopback fixture used by socket-path tests. */
+struct LoopbackPair {
+	WinsockBootstrap _ws;
+	SOCKET srv = INVALID_SOCKET;
+	SOCKET cli = INVALID_SOCKET;
+	struct sockaddr_in srv_addr {};
+
+	LoopbackPair()
+	{
+		srv = socket(AF_INET, SOCK_DGRAM, 0);
+		cli = socket(AF_INET, SOCK_DGRAM, 0);
+		srv_addr.sin_family = AF_INET;
+		srv_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+		srv_addr.sin_port = 0;
+		bind(srv, (struct sockaddr *)&srv_addr, sizeof(srv_addr));
+		int alen = sizeof(srv_addr);
+		getsockname(srv, (struct sockaddr *)&srv_addr, &alen);
+	}
+
+	~LoopbackPair()
+	{
+		if (srv != INVALID_SOCKET) { closesocket(srv); }
+
+		if (cli != INVALID_SOCKET) { closesocket(cli); }
+	}
+};
+
+} // namespace
+
+/* Argument validation -------------------------------------------------- */
+
+TEST(WindowsShimPoll, NegativeTimeoutBelowMinusOneRejected)
+{
+	struct pollfd fd;
+	fd.fd = -1;
+	fd.events = 0;
+	fd.revents = 0;
+	errno = 0;
+	int rc = poll(&fd, 1, -42);
+	EXPECT_EQ(rc, -1);
+	EXPECT_EQ(errno, EINVAL);
+}
+
+TEST(WindowsShimPoll, NullFdsWithCountRejected)
+{
+	errno = 0;
+	int rc = poll(nullptr, 1, 0);
+	EXPECT_EQ(rc, -1);
+	EXPECT_EQ(errno, EFAULT);
+}
+
+TEST(WindowsShimPoll, ZeroNfdsZeroTimeoutReturnsZero)
+{
+	auto t0 = std::chrono::steady_clock::now();
+	int rc = poll(nullptr, 0, 0);
+	EXPECT_EQ(rc, 0);
+	auto dt = std::chrono::duration_cast<std::chrono::milliseconds>(
+			  std::chrono::steady_clock::now() - t0).count();
+	EXPECT_LT(dt, 50);
+}
+
+TEST(WindowsShimPoll, ZeroNfdsPositiveTimeoutSleeps)
+{
+	auto t0 = std::chrono::steady_clock::now();
+	int rc = poll(nullptr, 0, 30);
+	EXPECT_EQ(rc, 0);
+	auto dt = std::chrono::duration_cast<std::chrono::milliseconds>(
+			  std::chrono::steady_clock::now() - t0).count();
+	EXPECT_GE(dt, 25);
+}
+
+/* fd-classification helpers -------------------------------------------- */
+
+TEST(WindowsShimPoll, IgnoredFdHelper)
+{
+	EXPECT_NE(px4_windows_poll_fd_ignored((SOCKET) - 1), 0);
+	EXPECT_NE(px4_windows_poll_fd_ignored((SOCKET) - 5), 0);
+	EXPECT_EQ(px4_windows_poll_fd_ignored((SOCKET)0), 0);
+}
+
+TEST(WindowsShimPoll, ErrnoFromWsaMapping)
+{
+	EXPECT_EQ(px4_windows_poll_errno_from_wsa(WSAEINTR), EINTR);
+	EXPECT_EQ(px4_windows_poll_errno_from_wsa(WSAEINVAL), EINVAL);
+	EXPECT_EQ(px4_windows_poll_errno_from_wsa(WSAENOBUFS), ENOMEM);
+	EXPECT_EQ(px4_windows_poll_errno_from_wsa(0xBEEF), EBADF);
+}
+
+TEST(WindowsShimPoll, ReadyEventsMask)
+{
+	EXPECT_EQ(px4_windows_poll_ready_events(POLLIN, POLLIN | POLLOUT), POLLIN);
+	EXPECT_EQ(px4_windows_poll_ready_events(POLLIN, POLLOUT), 0);
+	EXPECT_EQ(px4_windows_poll_ready_events(0, POLLIN), 0);
+}
+
+TEST(WindowsShimPoll, DiskReventsAlwaysReady)
+{
+	EXPECT_EQ(px4_windows_poll_disk_revents(POLLIN), POLLIN);
+	EXPECT_EQ(px4_windows_poll_disk_revents(POLLOUT), POLLOUT);
+	EXPECT_EQ(px4_windows_poll_disk_revents(0), 0);
+}
+
+TEST(WindowsShimPoll, ClassifyIgnoredFd)
+{
+	HANDLE h = nullptr;
+	DWORD ft = 0;
+	enum px4_windows_poll_fd_kind k =
+		px4_windows_poll_classify_fd((SOCKET) - 1, &h, &ft);
+	EXPECT_EQ(k, PX4_WINDOWS_POLL_FD_IGNORED);
+	EXPECT_EQ(h, INVALID_HANDLE_VALUE);
+	EXPECT_EQ(ft, FILE_TYPE_UNKNOWN);
+}
+
+TEST(WindowsShimPoll, ClassifyInvalidFd)
+{
+	WinsockBootstrap _ws;
+	HANDLE h = nullptr;
+	DWORD ft = 0;
+	/* A very high CRT-fd-domain value with no backing handle. */
+	enum px4_windows_poll_fd_kind k =
+		px4_windows_poll_classify_fd((SOCKET)999999, &h, &ft);
+	EXPECT_EQ(k, PX4_WINDOWS_POLL_FD_INVALID);
+}
+
+TEST(WindowsShimPoll, ClassifyPipeFd)
+{
+	int p[2] = { -1, -1 };
+	ASSERT_EQ(_pipe(p, 4096, _O_BINARY), 0);
+	HANDLE h = nullptr;
+	DWORD ft = 0;
+	enum px4_windows_poll_fd_kind k =
+		px4_windows_poll_classify_fd((SOCKET)p[0], &h, &ft);
+	EXPECT_EQ(k, PX4_WINDOWS_POLL_FD_PIPE);
+	EXPECT_NE(h, INVALID_HANDLE_VALUE);
+	EXPECT_EQ(ft, (DWORD)FILE_TYPE_PIPE);
+	_close(p[0]);
+	_close(p[1]);
+}
+
+TEST(WindowsShimPoll, ClassifyDiskFd)
+{
+	char path[MAX_PATH];
+	GetTempPathA(sizeof(path), path);
+	strcat_s(path, sizeof(path), "px4_poll_test.dat");
+	int fd = _open(path, _O_CREAT | _O_RDWR | _O_BINARY, _S_IREAD | _S_IWRITE);
+	ASSERT_GE(fd, 0);
+	HANDLE h = nullptr;
+	DWORD ft = 0;
+	enum px4_windows_poll_fd_kind k =
+		px4_windows_poll_classify_fd((SOCKET)fd, &h, &ft);
+	EXPECT_EQ(k, PX4_WINDOWS_POLL_FD_DISK);
+	EXPECT_EQ(ft, (DWORD)FILE_TYPE_DISK);
+	_close(fd);
+	DeleteFileA(path);
+}
+
+TEST(WindowsShimPoll, ClassifySocketFd)
+{
+	WinsockBootstrap _ws;
+	SOCKET s = socket(AF_INET, SOCK_DGRAM, 0);
+	ASSERT_NE(s, INVALID_SOCKET);
+	HANDLE h = nullptr;
+	DWORD ft = 0;
+	enum px4_windows_poll_fd_kind k =
+		px4_windows_poll_classify_fd(s, &h, &ft);
+	EXPECT_EQ(k, PX4_WINDOWS_POLL_FD_SOCKET);
+	EXPECT_EQ(h, INVALID_HANDLE_VALUE);
+	closesocket(s);
+}
+
+/* poll() integration --------------------------------------------------- */
+
+TEST(WindowsShimPoll, OnlyIgnoredFdShortCircuitTimeoutZero)
+{
+	struct pollfd fds[2];
+	fds[0].fd = -1;
+	fds[0].events = POLLIN;
+	fds[0].revents = 0xff;
+	fds[1].fd = -1;
+	fds[1].events = POLLOUT;
+	fds[1].revents = 0xff;
+	int rc = poll(fds, 2, 0);
+	EXPECT_EQ(rc, 0);
+	EXPECT_EQ(fds[0].revents, 0);
+	EXPECT_EQ(fds[1].revents, 0);
+}
+
+TEST(WindowsShimPoll, SocketWriteAlwaysReady)
+{
+	LoopbackPair pair;
+	struct pollfd pf;
+	pf.fd = (int)pair.cli;
+	pf.events = POLLOUT;
+	pf.revents = 0;
+	int rc = poll(&pf, 1, 0);
+	EXPECT_GE(rc, 0);
+	/* Writable on a fresh UDP socket. */
+	EXPECT_TRUE((pf.revents & POLLOUT) || rc == 0);
+}
+
+TEST(WindowsShimPoll, SocketReadReadyAfterSendto)
+{
+	LoopbackPair pair;
+	const char msg[] = "x";
+	ASSERT_EQ(sendto(pair.cli, msg, (int)sizeof(msg), 0,
+			 (struct sockaddr *)&pair.srv_addr, sizeof(pair.srv_addr)),
+		  (int)sizeof(msg));
+	/* Give the kernel a moment to deliver. */
+	struct pollfd pf;
+	pf.fd = (int)pair.srv;
+	pf.events = POLLIN;
+	pf.revents = 0;
+	int rc = poll(&pf, 1, 200);
+	EXPECT_EQ(rc, 1);
+	EXPECT_TRUE((pf.revents & POLLIN) != 0);
+}
+
+TEST(WindowsShimPoll, SocketTimeoutNoData)
+{
+	LoopbackPair pair;
+	struct pollfd pf;
+	pf.fd = (int)pair.srv;
+	pf.events = POLLIN;
+	pf.revents = 0;
+	auto t0 = std::chrono::steady_clock::now();
+	int rc = poll(&pf, 1, 30);
+	EXPECT_EQ(rc, 0);
+	auto dt = std::chrono::duration_cast<std::chrono::milliseconds>(
+			  std::chrono::steady_clock::now() - t0).count();
+	EXPECT_GE(dt, 20);
+}
+
+TEST(WindowsShimPoll, PipeWritableImmediately)
+{
+	int p[2] = { -1, -1 };
+	ASSERT_EQ(_pipe(p, 4096, _O_BINARY), 0);
+	struct pollfd pf;
+	pf.fd = p[1];
+	pf.events = POLLOUT;
+	pf.revents = 0;
+	int rc = poll(&pf, 1, 0);
+	EXPECT_EQ(rc, 1);
+	EXPECT_TRUE((pf.revents & POLLOUT) != 0);
+	_close(p[0]);
+	_close(p[1]);
+}
+
+TEST(WindowsShimPoll, PipeReadableAfterWrite)
+{
+	int p[2] = { -1, -1 };
+	ASSERT_EQ(_pipe(p, 4096, _O_BINARY), 0);
+	const char msg[] = "ping";
+	ASSERT_EQ(_write(p[1], msg, (unsigned)sizeof(msg)), (int)sizeof(msg));
+	struct pollfd pf;
+	pf.fd = p[0];
+	pf.events = POLLIN;
+	pf.revents = 0;
+	int rc = poll(&pf, 1, 200);
+	EXPECT_EQ(rc, 1);
+	EXPECT_TRUE((pf.revents & POLLIN) != 0);
+	_close(p[0]);
+	_close(p[1]);
+}
+
+TEST(WindowsShimPoll, PipeBrokenSetsHup)
+{
+	int p[2] = { -1, -1 };
+	ASSERT_EQ(_pipe(p, 4096, _O_BINARY), 0);
+	_close(p[1]);
+	struct pollfd pf;
+	pf.fd = p[0];
+	pf.events = POLLIN;
+	pf.revents = 0;
+	int rc = poll(&pf, 1, 50);
+	EXPECT_GE(rc, 1);
+	EXPECT_TRUE((pf.revents & (POLLHUP | POLLIN)) != 0);
+	_close(p[0]);
+}
+
+TEST(WindowsShimPoll, DiskFdAlwaysReady)
+{
+	char path[MAX_PATH];
+	GetTempPathA(sizeof(path), path);
+	strcat_s(path, sizeof(path), "px4_poll_disk.dat");
+	int fd = _open(path, _O_CREAT | _O_RDWR | _O_BINARY, _S_IREAD | _S_IWRITE);
+	ASSERT_GE(fd, 0);
+	struct pollfd pf;
+	pf.fd = fd;
+	pf.events = POLLIN | POLLOUT;
+	pf.revents = 0;
+	int rc = poll(&pf, 1, 0);
+	EXPECT_EQ(rc, 1);
+	EXPECT_TRUE((pf.revents & POLLIN) != 0);
+	EXPECT_TRUE((pf.revents & POLLOUT) != 0);
+	_close(fd);
+	DeleteFileA(path);
+}
+
+TEST(WindowsShimPoll, MixedSocketAndPipe)
+{
+	LoopbackPair pair;
+	int p[2] = { -1, -1 };
+	ASSERT_EQ(_pipe(p, 4096, _O_BINARY), 0);
+	const char msg[] = "z";
+	ASSERT_EQ(_write(p[1], msg, (unsigned)sizeof(msg)), (int)sizeof(msg));
+	struct pollfd fds[2];
+	fds[0].fd = p[0];
+	fds[0].events = POLLIN;
+	fds[0].revents = 0;
+	fds[1].fd = (int)pair.srv;
+	fds[1].events = POLLIN;
+	fds[1].revents = 0;
+	int rc = poll(fds, 2, 100);
+	EXPECT_GE(rc, 1);
+	EXPECT_TRUE((fds[0].revents & POLLIN) != 0);
+	_close(p[0]);
+	_close(p[1]);
+}
+
+TEST(WindowsShimPoll, InvalidFdReturnsPollnval)
+{
+	struct pollfd pf;
+	pf.fd = 999999; /* deliberately bogus */
+	pf.events = POLLIN;
+	pf.revents = 0;
+	int rc = poll(&pf, 1, 0);
+	EXPECT_GE(rc, 1);
+	EXPECT_TRUE((pf.revents & POLLNVAL) != 0);
+}
+
+#endif // _WIN32
+
+TEST(WindowsShimPoll, BuildSentinel)
+{
+	SUCCEED();
+}