diff --git a/python/private/toolchains_repo.bzl b/python/private/toolchains_repo.bzl
--- a/python/private/toolchains_repo.bzl
+++ b/python/private/toolchains_repo.bzl
@@ -313,6 +313,23 @@
     rctx.file("BUILD.bazel", _HOST_TOOLCHAIN_BUILD_CONTENT)
 
     os_name = repo_utils.get_platforms_os_name(rctx)
+
+    # FreeBSD and other unsupported platforms: fall back to system Python.
+    if os_name not in ["linux", "windows", "osx"]:
+        result = rctx.execute(["which", "python3"])
+        if result.return_code != 0:
+            fail("rules_python: Cannot find system python3 for host OS '{}'. Install python3 in PATH.".format(os_name))
+        python_path = result.stdout.strip()
+        rctx.symlink(rctx.path(python_path), "python")
+
+        # Symlink lib so PYTHONHOME points to a usable prefix.
+        prefix_result = rctx.execute([python_path, "-c", "import sys; print(sys.prefix)"])
+        if prefix_result.return_code == 0:
+            prefix = prefix_result.stdout.strip()
+            rctx.symlink(rctx.path(prefix + "/lib"), "lib")
+
+        return
+
     impl_repo_name = _get_host_impl_repo_name(
         rctx = rctx,
         logger = repo_utils.logger(rctx),