diff --git a/platforms/posix/cmake/px4_impl_os.cmake b/platforms/posix/cmake/px4_impl_os.cmake
index e285bfcc48c..39ae7e875c7 100644
--- a/platforms/posix/cmake/px4_impl_os.cmake
+++ b/platforms/posix/cmake/px4_impl_os.cmake
@@ -196,8 +196,17 @@ function(px4_os_add_flags)
 				)
 		endif()
 
-	else()
+	elseif(CYGWIN)
+		set(added_definitions
+			-D__PX4_POSIX
+			-D__PX4_CYGWIN
+			-D_GNU_SOURCE
+			-D__USE_LINUX_IOCTL_DEFS
+			-Dnoreturn_function=__attribute__\(\(noreturn\)\)
+			-U __CUSTOM_FILE_IO__
+			)
 
+	else()
 		set(added_definitions
 			-D__PX4_POSIX
 			-D__PX4_LINUX
diff --git a/src/lib/rc/dsm.cpp b/src/lib/rc/dsm.cpp
index 383d5882905..b94e77b514a 100644
--- a/src/lib/rc/dsm.cpp
+++ b/src/lib/rc/dsm.cpp
@@ -52,7 +52,7 @@
 #include "common_rc.h"
 #include <drivers/drv_hrt.h>
 
-#if defined (__PX4_LINUX) || defined (__PX4_DARWIN) || defined(__PX4_QURT)
+#if defined (__PX4_LINUX) || defined (__PX4_DARWIN) || defined(__PX4_CYGWIN) || defined(__PX4_QURT)
 #define dsm_udelay(arg) usleep(arg)
 #else
 #include <nuttx/arch.h>
diff --git a/src/lib/version/version.c b/src/lib/version/version.c
index d5182f0914e..67069d753e3 100644
--- a/src/lib/version/version.c
+++ b/src/lib/version/version.c
@@ -253,8 +253,8 @@ uint32_t px4_board_version(void)
 
 uint32_t px4_os_version(void)
 {
-#if defined(__PX4_DARWIN)
-	return 0; //TODO: implement version for Darwin
+#if defined(__PX4_DARWIN) || defined(__PX4_CYGWIN) || defined(__PX4_QURT)
+	return 0; //TODO: implement version for Darwin, Cygwin, QuRT
 #elif defined(__PX4_LINUX)
 	struct utsname name;
 
@@ -273,8 +273,6 @@ uint32_t px4_os_version(void)
 		return 0;
 	}
 
-#elif defined(__PX4_QURT)
-	return 0; //TODO: implement version for QuRT
 #elif defined(__PX4_NUTTX)
 	return version_tag_to_number(NUTTX_GIT_TAG_STR);
 #else
@@ -301,6 +299,8 @@ const char *px4_os_name(void)
 	return "QuRT";
 #elif defined(__PX4_NUTTX)
 	return "NuttX";
+#elif defined(__PX4_CYGWIN)
+	return "Cygwin";
 #else
 # error "px4_os_name not implemented for current OS"
 #endif
diff --git a/src/modules/mavlink/mavlink_main.cpp b/src/modules/mavlink/mavlink_main.cpp
index 41bb077aa1c..7d96c4962d3 100644
--- a/src/modules/mavlink/mavlink_main.cpp
+++ b/src/modules/mavlink/mavlink_main.cpp
@@ -836,7 +836,7 @@ int Mavlink::mavlink_open_uart(int baud, const char *uart_name)
 		_rstatus.type = telemetry_status_s::TELEMETRY_STATUS_RADIO_TYPE_USB;
 	}
 
-#if defined (__PX4_LINUX) || defined (__PX4_DARWIN)
+#if defined(__PX4_LINUX) || defined(__PX4_DARWIN) || defined(__PX4_CYGWIN)
 	/* Put in raw mode */
 	cfmakeraw(&uart_config);
 #endif
@@ -933,11 +933,11 @@ Mavlink::get_free_tx_buf()
 
 	} else {
 		// No FIONSPACE on Linux todo:use SIOCOUTQ  and queue size to emulate FIONSPACE
-#if !defined(__PX4_LINUX) && !defined(__PX4_DARWIN)
-		(void) ioctl(_uart_fd, FIONSPACE, (unsigned long)&buf_free);
-#else
+#if defined(__PX4_LINUX) || defined(__PX4_DARWIN) || defined(__PX4_CYGWIN)
 		//Linux cp210x does not support TIOCOUTQ
 		buf_free = 256;
+#else
+		(void) ioctl(_uart_fd, FIONSPACE, (unsigned long)&buf_free);
 #endif
 
 		if (get_flow_control_enabled() && buf_free < FLOW_CONTROL_DISABLE_THRESHOLD) {
@@ -1084,7 +1084,7 @@ Mavlink::send_bytes(const uint8_t *buf, unsigned packet_len)
 void
 Mavlink::find_broadcast_address()
 {
-#if defined (__PX4_LINUX) || defined (__PX4_DARWIN)
+#if defined(__PX4_LINUX) || defined(__PX4_DARWIN) || defined(__PX4_CYGWIN)
 	struct ifconf ifconf;
 	int ret;
 
@@ -1231,7 +1231,7 @@ Mavlink::find_broadcast_address()
 void
 Mavlink::init_udp()
 {
-#if defined (__PX4_LINUX) || defined (__PX4_DARWIN)
+#if defined (__PX4_LINUX) || defined (__PX4_DARWIN) || defined(__PX4_CYGWIN)
 
 	PX4_DEBUG("Setting up UDP with port %d", _network_port);
 
diff --git a/src/modules/mavlink/mavlink_shell.cpp b/src/modules/mavlink/mavlink_shell.cpp
index 7d453b06dc6..7ffb8911a17 100644
--- a/src/modules/mavlink/mavlink_shell.cpp
+++ b/src/modules/mavlink/mavlink_shell.cpp
@@ -50,6 +50,10 @@
 #include <nshlib/nshlib.h>
 #endif /* __PX4_NUTTX */
 
+#ifdef __PX4_CYGWIN
+#include <asm/socket.h>
+#endif
+
 
 MavlinkShell::MavlinkShell()
 {
diff --git a/src/modules/systemlib/print_load_posix.c b/src/modules/systemlib/print_load_posix.c
index 5578407da13..dcf01b66a50 100644
--- a/src/modules/systemlib/print_load_posix.c
+++ b/src/modules/systemlib/print_load_posix.c
@@ -91,15 +91,10 @@ void print_load(uint64_t t, int fd, struct print_load_s *print_state)
 		clear_line = CL;
 	}
 
-#if defined (__PX4_LINUX)
-	dprintf(fd, "%sTOP NOT IMPLEMENTED ON LINUX\n",
-		clear_line);
+#if defined(__PX4_LINUX) || defined(__PX4_CYGWIN) || defined(__PX4_QURT)
+	dprintf(fd, "%sTOP NOT IMPLEMENTED ON LINUX, QURT, WINDOWS (ONLY ON NUTTX, APPLE)\n", clear_line);
 
-#elif defined (__PX4_QURT)
-	dprintf(fd, "%sTOP NOT IMPLEMENTED ON QURT\n",
-		clear_line);
-
-#elif defined (__PX4_DARWIN)
+#elif defined(__PX4_DARWIN)
 	pid_t pid = getpid();   //-- this is the process id you need info for
 	task_t task_handle;
 	task_for_pid(mach_task_self(), pid, &task_handle);
diff --git a/src/platforms/posix/px4_layer/px4_log.c b/src/platforms/posix/px4_layer/px4_log.c
index 6f40bd52776..cf1599a01ff 100644
--- a/src/platforms/posix/px4_layer/px4_log.c
+++ b/src/platforms/posix/px4_layer/px4_log.c
@@ -1,7 +1,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <px4_log.h>
-#ifdef __PX4_POSIX
+#if defined(__PX4_POSIX) && !defined(__PX4_CYGWIN)
 #include <execinfo.h>
 #endif
 #include <uORB/uORB.h>
@@ -34,7 +34,7 @@ void px4_log_initialize(void)
 
 void px4_backtrace()
 {
-#ifdef __PX4_POSIX
+#if defined(__PX4_POSIX) && !defined(__PX4_CYGWIN)
 	void *buffer[10];
 	char **callstack;
 	int bt_size;
diff --git a/src/platforms/posix/px4_layer/px4_posix_tasks.cpp b/src/platforms/posix/px4_layer/px4_posix_tasks.cpp
index ee845b5fce2..3e69b542a39 100644
--- a/src/platforms/posix/px4_layer/px4_posix_tasks.cpp
+++ b/src/platforms/posix/px4_layer/px4_posix_tasks.cpp
@@ -212,6 +212,11 @@ px4_task_t px4_task_spawn_cmd(const char *name, int scheduler, int priority, int
 		return (rv < 0) ? rv : -rv;
 	}
 
+#ifdef __PX4_CYGWIN
+	/* Priorities on Windows are defined a lot differently */
+	priority = SCHED_PRIORITY_DEFAULT;
+#endif
+
 	param.sched_priority = priority;
 
 	rv = pthread_attr_setschedparam(&attr, &param);
diff --git a/src/platforms/posix/px4_layer/px4_sem.cpp b/src/platforms/posix/px4_layer/px4_sem.cpp
index 59bac76bd93..6e28af7b592 100644
--- a/src/platforms/posix/px4_layer/px4_sem.cpp
+++ b/src/platforms/posix/px4_layer/px4_sem.cpp
@@ -45,7 +45,7 @@
 #include <pthread.h>
 #include <errno.h>
 
-#ifdef __PX4_DARWIN
+#if defined(__PX4_DARWIN) || defined(__PX4_CYGWIN)
 
 #include <px4_posix.h>
 
diff --git a/src/platforms/px4_defines.h b/src/platforms/px4_defines.h
index 797ee9a4c99..b6d86950603 100644
--- a/src/platforms/px4_defines.h
+++ b/src/platforms/px4_defines.h
@@ -152,7 +152,9 @@ using ::isfinite;
  ****************************************************************************/
 
 // Flag is meaningless on Linux
+#ifndef O_BINARY
 #define O_BINARY 0
+#endif
 
 // mode for open with O_CREAT
 #define PX4_O_MODE_777 (S_IRWXU | S_IRWXG | S_IRWXO)
diff --git a/src/platforms/px4_sem.h b/src/platforms/px4_sem.h
index d6d467f61bf..aa8c9009ec6 100644
--- a/src/platforms/px4_sem.h
+++ b/src/platforms/px4_sem.h
@@ -50,7 +50,7 @@
 #define sem_setprotocol(s,p)
 #endif
 
-#ifdef __PX4_DARWIN
+#if defined(__PX4_DARWIN) || defined(__PX4_CYGWIN)
 
 __BEGIN_DECLS
 
diff --git a/src/platforms/px4_tasks.h b/src/platforms/px4_tasks.h
index 2b08b755367..104593735b6 100644
--- a/src/platforms/px4_tasks.h
+++ b/src/platforms/px4_tasks.h
@@ -69,11 +69,7 @@ typedef int px4_task_t;
 
 /** Default scheduler type */
 #define SCHED_DEFAULT	SCHED_FIFO
-#ifdef __PX4_LINUX
-#define SCHED_PRIORITY_MAX sched_get_priority_max(SCHED_FIFO)
-#define SCHED_PRIORITY_MIN sched_get_priority_min(SCHED_FIFO)
-#define SCHED_PRIORITY_DEFAULT (((sched_get_priority_max(SCHED_FIFO) - sched_get_priority_min(SCHED_FIFO)) / 2) + sched_get_priority_min(SCHED_FIFO))
-#elif defined(__PX4_DARWIN)
+#if defined(__PX4_LINUX) || defined(__PX4_DARWIN) || defined(__PX4_CYGWIN)
 #define SCHED_PRIORITY_MAX sched_get_priority_max(SCHED_FIFO)
 #define SCHED_PRIORITY_MIN sched_get_priority_min(SCHED_FIFO)
 #define SCHED_PRIORITY_DEFAULT (((sched_get_priority_max(SCHED_FIFO) - sched_get_priority_min(SCHED_FIFO)) / 2) + sched_get_priority_min(SCHED_FIFO))
diff --git a/src/platforms/px4_time.h b/src/platforms/px4_time.h
index 2d310b54b99..b123361c251 100644
--- a/src/platforms/px4_time.h
+++ b/src/platforms/px4_time.h
@@ -16,7 +16,7 @@ __EXPORT unsigned int sleep(unsigned int sec);
 
 __END_DECLS
 
-#elif defined(__PX4_LINUX) || defined(__PX4_NUTTX) || defined(__PX4_DARWIN)
+#elif defined(__PX4_LINUX) || defined(__PX4_NUTTX) || defined(__PX4_DARWIN) || defined(__PX4_CYGWIN)
 
 #define px4_clock_gettime clock_gettime
 #define px4_clock_settime clock_settime