--- src/third_party/boost/BUILD.bazel.orig	2026-10-14 17:59:44 UTC
+++ src/third_party/boost/BUILD.bazel
@@ -113,6 +113,7 @@ BOOST_DEFINES = [
 
 BOOST_DEFINES = [
     "BOOST_BIND_GLOBAL_PLACEHOLDERS",
+    "BOOST_FILESYSTEM_NO_CXX20_ATOMIC_REF",
 ]
 
 BOOST_LIB_INCLUDES = ["."] + glob(
@@ -221,6 +222,10 @@ mongo_cc_library(
             "libs/thread/src/pthread/once.cpp",
             "libs/thread/src/pthread/thread.cpp",
         ],
+        "@platforms//os:freebsd": [
+            "libs/thread/src/pthread/once.cpp",
+            "libs/thread/src/pthread/thread.cpp",
+        ],
         "@platforms//os:windows": [
             "libs/thread/src/win32/thread.cpp",
             "libs/thread/src/win32/thread_primitives.cpp",
@@ -238,6 +243,9 @@ mongo_cc_library(
         "@platforms//os:wasi": [
             "libs/thread/src/pthread/once_atomic.cpp",
         ],
+        "@platforms//os:freebsd": [
+            "libs/thread/src/pthread/once_atomic.cpp",
+        ],
         "//conditions:default": [],
     }),
     copts = BOOST_COPTS,
@@ -250,6 +258,9 @@ mongo_cc_library(
             "BOOST_THREAD_PTHREAD",
         ],
         "@platforms//os:wasi": [
+            "BOOST_THREAD_PTHREAD",
+        ],
+        "@platforms//os:freebsd": [
             "BOOST_THREAD_PTHREAD",
         ],
         "@platforms//os:windows": [