diff --git a/Makefile b/Makefile
index c06d32ee..cf669915 100644
--- a/Makefile
+++ b/Makefile
@@ -140,6 +140,8 @@ ifeq ($(OSTYPE),Linux)
 INCLUDE := -I/usr/include
 else ifeq ($(OSTYPE),FreeBSD)
 INCLUDE := -I/usr/local/include
+else ifeq ($(OSTYPE),OpenBSD)
+INCLUDE := -I/usr/local/include
 endif
 
 # ----------
@@ -149,6 +151,8 @@ ifeq ($(OSTYPE),Linux)
 LDFLAGS := -L/usr/lib -lm -ldl
 else ifeq ($(OSTYPE),FreeBSD)
 LDFLAGS := -L/usr/local/lib -lm
+else ifeq ($(OSTYPE),OpenBSD)
+LDFLAGS := -L/usr/local/lib -lm
 else ifeq ($(OSTYPE),Windows)
 LDFLAGS := -lws2_32 -lwinmm
 endif
@@ -271,8 +275,12 @@ release/quake2 : LDFLAGS += -lvorbis -lvorbisfile -logg
 endif
 
 ifeq ($(WITH_OPENAL),yes)
+ifeq ($(OSTYPE), OpenBSD)
+release/quake2 : CFLAGS += -DUSE_OPENAL -DDEFAULT_OPENAL_DRIVER='"libopenal.so"'
+else
 release/quake2 : CFLAGS += -DUSE_OPENAL -DDEFAULT_OPENAL_DRIVER='"libopenal.so.1"'
 endif
+endif
 
 ifeq ($(WITH_ZIP),yes)
 release/quake2 : CFLAGS += -DZIP -DNOUNCRYPT
diff --git a/src/backends/unix/hunk.c b/src/backends/unix/hunk.c
index 8a619e7f..cc623f16 100644
--- a/src/backends/unix/hunk.c
+++ b/src/backends/unix/hunk.c
@@ -32,10 +32,11 @@
 #include <sys/mman.h>
 #include <errno.h>
 #include <sys/time.h>
+#include <unistd.h>
 
 #include "../../common/header/common.h"
 
-#if defined(__FreeBSD__)
+#if defined(__FreeBSD__) || defined(__OpenBSD__)
  #include <machine/param.h>
  #define MAP_ANONYMOUS MAP_ANON
 #endif
@@ -87,7 +88,9 @@ Hunk_End(void)
 {
 	byte *n = NULL;
 
-#if defined(__FreeBSD__)
+#if defined(__linux__)
+	n = (byte *)mremap(membase, maxhunksize, curhunksize + sizeof(int), 0);
+#elif defined(__FreeBSD__)
 	size_t old_size = maxhunksize;
 	size_t new_size = curhunksize + sizeof(int);
 	void *unmap_base;
@@ -106,10 +109,37 @@ Hunk_End(void)
 		unmap_len = old_size - new_size;
 		n = munmap(unmap_base, unmap_len) + membase;
 	}
-#endif
+#else
+ #ifndef round_page
+ #define round_page(x) (((size_t)(x) + (page_size - 1)) / page_size) * \
+	     page_size
+ #endif
 
-#if defined(__linux__)
-	n = (byte *)mremap(membase, maxhunksize, curhunksize + sizeof(int), 0);
+	size_t old_size = maxhunksize;
+	size_t new_size = curhunksize + sizeof(int);
+	void *unmap_base;
+	size_t unmap_len;
+	long page_size;
+
+	page_size = sysconf(_SC_PAGESIZE);
+	if (page_size == -1)
+	{
+		Sys_Error("Hunk_End: sysconf _SC_PAGESIZE failed (%d)", errno);
+	}
+
+	new_size = round_page(new_size);
+	old_size = round_page(old_size);
+
+	if (new_size > old_size)
+	{
+		n = 0; /* error */
+	}
+	else if (new_size < old_size)
+	{
+		unmap_base = (caddr_t)(membase + new_size);
+		unmap_len = old_size - new_size;
+		n = munmap(unmap_base, unmap_len) + membase;
+	}
 #endif
 
 	if (n != membase)
diff --git a/src/common/header/common.h b/src/common/header/common.h
index 894c6e94..53d5275a 100644
--- a/src/common/header/common.h
+++ b/src/common/header/common.h
@@ -41,6 +41,8 @@
  #define BUILDSTRING "Linux"
 #elif defined __FreeBSD__
  #define BUILDSTRING "FreeBSD"
+#elif defined __OpenBSD__
+ #define BUILDSTRING "OpenBSD"
 #elif defined _WIN32
  #define BUILDSTRING "Windows"
 #else
@@ -65,6 +67,8 @@
 
 #ifdef _WIN32
  #define LIBGL "opengl32.dll"
+#elif defined __OpenBSD__
+ #define LIBGL "libGL.so"
 #else
  #define LIBGL "libGL.so.1"
 #endif
diff --git a/src/game/savegame/savegame.c b/src/game/savegame/savegame.c
index fd8de901..df149db4 100644
--- a/src/game/savegame/savegame.c
+++ b/src/game/savegame/savegame.c
@@ -86,6 +86,8 @@
  */
 #if defined(__FreeBSD__)
  #define OS "FreeBSD"
+#elif defined(__OpenBSD__)
+ #define OS "OpenBSD"
 #elif defined(__linux__)
  #define OS "Linux"
 #elif defined(_WIN32)