diff --git a/libraries/AP_HAL_SITL/Scheduler.cpp b/libraries/AP_HAL_SITL/Scheduler.cpp
index d9a2a3ba3a..ccc40042e8 100644
--- a/libraries/AP_HAL_SITL/Scheduler.cpp
+++ b/libraries/AP_HAL_SITL/Scheduler.cpp
@@ -7,7 +7,7 @@
 #include <sys/time.h>
 #include <fenv.h>
 #include <AP_BoardConfig/AP_BoardConfig.h>
-#if defined (__clang__) || (defined (__APPLE__) && defined (__MACH__))
+#if defined (__clang__) || (defined (__APPLE__) && defined (__MACH__)) || defined (__OpenBSD__)
 #include <stdlib.h>
 #else
 #include <malloc.h>
@@ -385,7 +385,7 @@ bool Scheduler::thread_create(AP_HAL::MemberProc proc, const char *name, uint32_
         goto failed;
     }
 
-#if !defined(__APPLE__)
+#if !defined(__APPLE__) && !defined(__OpenBSD__)
     pthread_setname_np(thread, name);
 #endif
 
diff --git a/libraries/AP_HAL_SITL/UARTDriver.cpp b/libraries/AP_HAL_SITL/UARTDriver.cpp
index 39738637e0..e809f4a43b 100644
--- a/libraries/AP_HAL_SITL/UARTDriver.cpp
+++ b/libraries/AP_HAL_SITL/UARTDriver.cpp
@@ -714,6 +714,8 @@ bool UARTDriver::set_unbuffered_writes(bool on) {
     v &= ~O_NONBLOCK;
 #if defined(__APPLE__) && defined(__MACH__)
     fcntl(_fd, F_SETFL | F_NOCACHE, v | O_SYNC);
+#elif defined(__OpenBSD__)
+    fcntl(_fd, F_SETFL, v | O_SYNC);
 #else
     fcntl(_fd, F_SETFL, v | O_DIRECT | O_SYNC);
 #endif
diff --git a/libraries/AP_HAL_SITL/UART_utils.cpp b/libraries/AP_HAL_SITL/UART_utils.cpp
index a3dfcccc28..ca4628c57b 100644
--- a/libraries/AP_HAL_SITL/UART_utils.cpp
+++ b/libraries/AP_HAL_SITL/UART_utils.cpp
@@ -19,7 +19,7 @@
 
 #include "UARTDriver.h"
 
-#if defined(__CYGWIN__) || defined(__CYGWIN64__) || defined(__APPLE__)
+#if defined(__CYGWIN__) || defined(__CYGWIN64__) || defined(__APPLE__) || defined(__OpenBSD__)
 #define USE_TERMIOS
 #endif