--- a/toolchain/internal/common.bzl
+++ b/toolchain/internal/common.bzl
@@ -19,6 +19,8 @@
     ("linux", "riscv64"),
     ("darwin", "x86_64"),
     ("darwin", "aarch64"),
+    ("freebsd", "x86_64"),
+    ("freebsd", "aarch64"),
     ("none", "riscv32"),
     ("none", "wasm32"),
     ("none", "wasm64"),
@@ -135,7 +137,7 @@
 
     name = rctx.attr.exec_os
     if name:
-        if name in ("linux", "darwin", "none"):
+        if name in ("linux", "darwin", "freebsd", "none"):
             return name
         else:
             fail("Unsupported value for exec_os: %s" % name)
@@ -149,11 +151,13 @@
         return "darwin"
     elif name.startswith("windows"):
         return "windows"
+    elif name == "freebsd":
+        return "freebsd"
     fail("Unsupported OS: " + name)
 
 def os_bzl(os):
     # Return the OS string as used in bazel platform constraints.
-    return {"darwin": "osx", "linux": "linux", "none": "none", "wasip1": "wasi"}[os]
+    return {"darwin": "osx", "linux": "linux", "freebsd": "freebsd", "none": "none", "wasip1": "wasi"}[os]
 
 def arch(rctx):
     arch = rctx.attr.exec_arch