diff --git a/CMakeLists.txt b/CMakeLists.txt
index 203e2c1..5fa37c2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -43,11 +43,15 @@ elseif(UNIX AND NOT APPLE)
         message(STATUS "ON LINUX WASM BUILD")
     elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
         message(STATUS "ON LINUX BUILD")
+    elseif(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
+        message(STATUS "ON FREEBSD BUILD")
     else()
         message(FATAL_ERROR "Unsupported operating system. Please create issue or contribute!")
     endif()
-    set(MGCLIENT_ON_LINUX TRUE)
-    add_definitions(-DMGCLIENT_ON_LINUX)
+    # Linux and FreeBSD share the same POSIX socket path in src/linux/,
+    # selected by MGCLIENT_ON_POSIX.
+    set(MGCLIENT_ON_POSIX TRUE)
+    add_definitions(-DMGCLIENT_ON_POSIX)
     set(MGCLIENT_FIND_LIBRARY_PREFIXES "${CMAKE_FIND_LIBRARY_PREFIXES}")
 elseif(APPLE)
     message(STATUS "ON APPLE BUILD")
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 6ede31e..f29626d 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -28,7 +28,7 @@ set(mgclient_src_files
         mgvalue.c)
 if(MGCLIENT_ON_APPLE)
     list(APPEND mgclient_src_files apple/mgsocket.c)
-elseif(MGCLIENT_ON_LINUX)
+elseif(MGCLIENT_ON_POSIX)
     list(APPEND mgclient_src_files linux/mgsocket.c)
 elseif(MGCLIENT_ON_WINDOWS)
     list(APPEND mgclient_src_files windows/mgsocket.c)
diff --git a/src/linux/mgcommon.h b/src/linux/mgcommon.h
index a2702aa..0b8f07f 100644
--- a/src/linux/mgcommon.h
+++ b/src/linux/mgcommon.h
@@ -15,6 +15,10 @@
 #ifndef MGCLIENT_LINUX_MGCOMMON_H
 #define MGCLIENT_LINUX_MGCOMMON_H
 
+#if defined(__FreeBSD__)
+#include <sys/endian.h>
+#else
 #include <endian.h>
+#endif
 
 #endif
diff --git a/src/linux/mgsocket.c b/src/linux/mgsocket.c
index 6adefd4..2bca678 100644
--- a/src/linux/mgsocket.c
+++ b/src/linux/mgsocket.c
@@ -102,15 +102,15 @@ int mg_socket_options(int sock, mg_session *session) {
     int optname;
     int optval;
   } socket_options[] = {// disable Nagle algorithm for performance reasons
-                        {SOL_TCP, TCP_NODELAY, 1},
+                        {IPPROTO_TCP, TCP_NODELAY, 1},
                         // turn keep-alive on
                         {SOL_SOCKET, SO_KEEPALIVE, 1},
                         // wait 20s before sending keep-alive packets
-                        {SOL_TCP, TCP_KEEPIDLE, 20},
+                        {IPPROTO_TCP, TCP_KEEPIDLE, 20},
                         // 4 keep-alive packets must fail to close
-                        {SOL_TCP, TCP_KEEPCNT, 4},
+                        {IPPROTO_TCP, TCP_KEEPCNT, 4},
                         // send keep-alive packets every 15s
-                        {SOL_TCP, TCP_KEEPINTVL, 15}};
+                        {IPPROTO_TCP, TCP_KEEPINTVL, 15}};
   const size_t OPTCNT = sizeof(socket_options) / sizeof(socket_options[0]);
 
   for (size_t i = 0; i < OPTCNT; ++i) {
diff --git a/src/mgcommon.h b/src/mgcommon.h
index bf2f04f..2aeac9a 100644
--- a/src/mgcommon.h
+++ b/src/mgcommon.h
@@ -23,9 +23,9 @@ extern "C" {
 #include "apple/mgcommon.h"
 #endif  // MGCLIENT_ON_APPLE
 
-#ifdef MGCLIENT_ON_LINUX
+#ifdef MGCLIENT_ON_POSIX
 #include "linux/mgcommon.h"
-#endif  // MGCLIENT_ON_LINUX
+#endif  // MGCLIENT_ON_POSIX
 
 #ifdef MGCLIENT_ON_WINDOWS
 #include "windows/mgcommon.h"
diff --git a/src/mgsocket.h b/src/mgsocket.h
index 96143a8..62d994c 100644
--- a/src/mgsocket.h
+++ b/src/mgsocket.h
@@ -28,7 +28,7 @@ extern "C" {
 #include <unistd.h>
 #endif  // MGCLIENT_ON_APPLE
 
-#ifdef MGCLIENT_ON_LINUX
+#ifdef MGCLIENT_ON_POSIX
 #include <arpa/inet.h>
 #include <errno.h>
 #include <netdb.h>
@@ -38,7 +38,7 @@ extern "C" {
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <unistd.h>
-#endif  // MGCLIENT_ON_LINUX
+#endif  // MGCLIENT_ON_POSIX
 
 #ifdef MGCLIENT_ON_WINDOWS
 #include <Ws2tcpip.h>
diff --git a/src/mgtransport.c b/src/mgtransport.c
index a134970..160daa4 100644
--- a/src/mgtransport.c
+++ b/src/mgtransport.c
@@ -17,11 +17,11 @@
 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>
-#ifdef MGCLIENT_ON_LINUX
+#ifdef MGCLIENT_ON_POSIX
 #ifndef __EMSCRIPTEN__
 #include <pthread.h>
 #endif
-#endif  // MGCLIENT_ON_LINUX
+#endif  // MGCLIENT_ON_POSIX
 
 #include "mgallocator.h"
 #include "mgclient.h"
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index cf079c0..3477ccf 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -45,7 +45,7 @@ add_gtest(client client.cpp)
 # We're mocking the mg_secure_transport_init function in the test.
 if(MGCLIENT_ON_APPLE)
     target_link_libraries(client -Wl,-alias,___wrap_mg_secure_transport_init,_mg_secure_transport_init)
-elseif(MGCLIENT_ON_LINUX)
+elseif(MGCLIENT_ON_POSIX)
     target_link_libraries(client -Wl,--wrap=mg_secure_transport_init)
 endif()
 add_gtest(transport transport.cpp)