diff --git a/build.sh b/build.sh
index 77de8ecdd..54d7b3be2 100755
--- a/build.sh
+++ b/build.sh
@@ -38,6 +38,11 @@ case "$os" in
 	plat_cflags="$plat_cflags -DAT_REMOVEDIR=0x200"
 	CC=clang
 	;;
+	FreeBSD)
+	plat_files="$plat_files ../src/compat/clearenv.c "
+	plat_files="$plat_files ../src/compat/dir_mutex.c "
+	plat_files="$plat_files ../src/compat/utimensat.c"
+	;;
 esac
 
 rm -rf build
diff --git a/src/tup/option.c b/src/tup/option.c
index 96b006a8a..d23bceab5 100644
--- a/src/tup/option.c
+++ b/src/tup/option.c
@@ -18,7 +18,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#if defined(__APPLE__) || defined(__FreeBSD__)
+#if defined(__APPLE__)
 #include <sys/sysctl.h>
 #elif defined(_WIN32)
 /* Don't let Windows define SLIST_ENTRY and conflict with bsd/queue.h */
@@ -290,9 +290,9 @@ static const char *cpu_number(void)
 	static char buf[10];
 
 	int count = 1;
-#if defined(__linux__) || defined(__sun__)
+#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__)
 	count = sysconf(_SC_NPROCESSORS_ONLN);
-#elif defined(__APPLE__) || defined(__FreeBSD__)
+#elif defined(__APPLE__)
 	int nm[2];
 	size_t len = 4;
 
diff --git a/src/tup/platform.c b/src/tup/platform.c
index eb176af2f..d5a71ef9d 100644
--- a/src/tup/platform.c
+++ b/src/tup/platform.c
@@ -23,6 +23,8 @@
 /* NOTE: Please keep the list in tup.1 in sync */
 #ifdef __linux__
 const char *tup_platform = "linux";
+#elif __FreeBSD__
+const char *tup_platform = "freebsd";
 #elif __sun__
 const char *tup_platform = "solaris";
 #elif __APPLE__
diff --git a/src/tup/server/fuse_fs.c b/src/tup/server/fuse_fs.c
index 51366a0c8..59a372418 100644
--- a/src/tup/server/fuse_fs.c
+++ b/src/tup/server/fuse_fs.c
@@ -25,6 +25,12 @@
 /* For pread()/pwrite() */
 #define _XOPEN_SOURCE 500
 #endif
+#ifdef __FreeBSD__
+/* For S_IFDIR */
+# define __XSI_VISIBLE 1
+/* For AT_SYMLINK_NOFOLLOW */
+# define __BSD_VISIBLE 1
+#endif
 
 #include "compat/utimensat.h"
 #include "tup_fuse_fs.h"
@@ -38,6 +44,10 @@
 #include <dirent.h>
 #include <errno.h>
 #include <sys/types.h>
+#ifdef __FreeBSD__
+# include <fcntl.h>
+# include <sys/stat.h>
+#endif
 
 static struct thread_root troot = THREAD_ROOT_INITIALIZER;
 static int server_mode = 0;
diff --git a/src/tup/server/fuse_server.c b/src/tup/server/fuse_server.c
index ed939a472..5dbb885cd 100644
--- a/src/tup/server/fuse_server.c
+++ b/src/tup/server/fuse_server.c
@@ -91,7 +91,7 @@ static int os_unmount(void)
 	}
 	return rc;
 }
-#elif defined(__APPLE__)
+#elif defined(__APPLE__) || defined(__FreeBSD__)
 static int os_unmount(void)
 {
 	if(unmount(TUP_MNT, MNT_FORCE) < 0) {
diff --git a/src/tup/server/master_fork.c b/src/tup/server/master_fork.c
index 2fdab2106..28c4e657e 100644
--- a/src/tup/server/master_fork.c
+++ b/src/tup/server/master_fork.c
@@ -33,6 +33,9 @@
 #include <errno.h>
 #include <sys/socket.h>
 #include <sys/wait.h>
+#ifdef __FreeBSD__
+# include <sys/param.h>
+#endif
 #include <sys/mount.h>
 #include <signal.h>
 
@@ -279,12 +282,18 @@ static int setup_subprocess(tupid_t sid, const char *job, const char *dir,
 			fprintf(stderr, "tup internal error: Trying to run sub-process in a chroot, but tup is not privileged.\n");
 			return -1;
 		}
-#ifdef __APPLE__
+#if defined(__APPLE__)
 		if(mount("devfs", dev, MNT_DONTBROWSE, NULL) < 0) {
 			perror("mount");
 			fprintf(stderr, "tup error: Unable to mount /dev into fuse file-system.\n");
 			return -1;
 		}
+#elif defined(__FreeBSD__)
+		if(mount("devfs", dev, 0, NULL) < 0) {
+			perror("mount");
+			fprintf(stderr, "tup error: Unable to mount /dev into fuse file-system.\n");
+			return -1;
+		}
 #else
 		/* The "tmpfs" argument is ignored since we use MS_BIND, but
 		 * valgrind complains about it if we use NULL.
@@ -548,7 +557,7 @@ static void *child_waiter(void *arg)
 	}
 	if(waiter->do_chroot && tup_privileged()) {
 		int rc;
-#ifdef __APPLE__
+#if defined(__APPLE__) || defined(__FreeBSD__)
 		rc = unmount(waiter->dev, MNT_FORCE);
 #else
 		rc = umount2(waiter->dev, MNT_FORCE);
diff --git a/tup.1 b/tup.1
index ea46faf2e..8c59be87e 100644
--- a/tup.1
+++ b/tup.1
@@ -528,7 +528,7 @@ In tup.config, comments are determined by a '#' character in the first column. T
 In this case, the @-variable "FOO" is explicitly set to "n".
 .TP
 .B @(TUP_PLATFORM)
-TUP_PLATFORM is a special @-variable. If CONFIG_TUP_PLATFORM is not set in the tup.config file, it has a default value according to the platform that tup itself was compiled in. Currently the default value is one of "linux", "solaris", "macosx", or "win32".
+TUP_PLATFORM is a special @-variable. If CONFIG_TUP_PLATFORM is not set in the tup.config file, it has a default value according to the platform that tup itself was compiled in. Currently the default value is one of "linux", "freebsd", "solaris", "macosx", or "win32".
 .TP
 .B @(TUP_ARCH)
 TUP_ARCH is another special @-variable. If CONFIG_TUP_ARCH is not set in the tup.config file, it has a default value according to the processor architecture that tup itself was compiled in. Currently the default value is one of "i386", "x86_64", "powerpc", "powerpc64", "ia64", "alpha", "sparc" or "arm".