diff --git a/BUILD b/BUILD
index ff484fe4ed..7c47752c20 100644
--- a/BUILD
+++ b/BUILD
@@ -614,6 +614,11 @@ cc_test(
         "upb/reflection/def_builder_test.cc",
         "upb/reflection/def_type.h",
     ],
+    # TODO(b/259158612): fix this test on Windows.
+    target_compatible_with = select({
+        "@platforms//os:windows": ["//third_party/bazel_platforms:incompatible"],
+        "//conditions:default": [],
+    }),
     deps = [
         ":descriptor_upb_proto",
         ":hash",
@@ -887,6 +892,10 @@ cc_binary(
     srcs = ["upb/conformance_upb.c"],
     copts = UPB_DEFAULT_COPTS,
     data = ["upb/conformance_upb_failures.txt"],
+    target_compatible_with = select({
+        "@platforms//os:windows": ["//third_party/bazel_platforms:incompatible"],
+        "//conditions:default": [],
+    }),
     deps = [
         ":conformance_proto_upb",
         ":conformance_proto_upbdefs",
@@ -917,6 +926,10 @@ sh_test(
         ":conformance_upb",
         "@com_google_protobuf//conformance:conformance_test_runner",
     ],
+    target_compatible_with = select({
+        "@platforms//os:windows": ["//third_party/bazel_platforms:incompatible"],
+        "//conditions:default": [],
+    }),
     deps = ["@bazel_tools//tools/bash/runfiles"],
 )
 
@@ -928,6 +941,10 @@ cc_binary(
         "-DREBUILD_MINITABLES",
     ],
     data = ["upb/conformance_upb_failures.txt"],
+    target_compatible_with = select({
+        "@platforms//os:windows": ["//third_party/bazel_platforms:incompatible"],
+        "//conditions:default": [],
+    }),
     deps = [
         ":conformance_proto_upb",
         ":conformance_proto_upbdefs",
diff --git a/python/BUILD b/python/BUILD
index 0c0d64a023..c20bd70145 100644
--- a/python/BUILD
+++ b/python/BUILD
@@ -202,6 +202,10 @@ py_extension(
         # casts between function pointers and object pointers.
         "-Wno-pedantic",
     ],
+    target_compatible_with = select({
+        "@platforms//os:windows": ["//third_party/bazel_platforms:incompatible"],
+        "//conditions:default": [],
+    }),
     deps = [
         "//:collections",
         "//:descriptor_upb_proto_reflection",
diff --git a/python/pb_unit_tests/pyproto_test_wrapper.bzl b/python/pb_unit_tests/pyproto_test_wrapper.bzl
index 8ea38789c0..bda44e95d7 100644
--- a/python/pb_unit_tests/pyproto_test_wrapper.bzl
+++ b/python/pb_unit_tests/pyproto_test_wrapper.bzl
@@ -31,6 +31,10 @@ def pyproto_test_wrapper(name, deps = []):
 #             "//net/proto2/python/internal:" + name + "_for_deps",
 #             "//net/proto2/python/public:use_upb_protos",
 #         ],
+#         target_compatible_with = select({
+#             "@platforms//os:windows": ["//third_party/bazel_platforms:incompatible"],
+#             "//conditions:default": [],
+#         }),
 #     )
 #
 # end:google_only
diff --git a/python/py_extension.bzl b/python/py_extension.bzl
index e41b22415c..7b918bc78e 100644
--- a/python/py_extension.bzl
+++ b/python/py_extension.bzl
@@ -2,7 +2,7 @@
 
 load("@bazel_skylib//lib:selects.bzl", "selects")
 
-def py_extension(name, srcs, copts, deps = []):
+def py_extension(name, srcs, copts, deps = [], **kwargs):
     """Creates a C++ library to extend python
 
     Args:
@@ -38,6 +38,7 @@ def py_extension(name, srcs, copts, deps = []):
             "//python:limited_api_3.10_win64": ["@nuget_python_x86-64_3.10.0//:python_limited_api"],
             "//conditions:default": ["@system_python//:python_headers"],
         }),
+        **kwargs
     )
 
     EXT_SUFFIX = ".abi3.so"
diff --git a/upb/hash/test.cc b/upb/hash/test.cc
index 63544d66e5..b1c10f7690 100644
--- a/upb/hash/test.cc
+++ b/upb/hash/test.cc
@@ -27,7 +27,6 @@
 
 #include <limits.h>
 #include <string.h>
-#include <sys/resource.h>
 
 #include <iostream>
 #include <map>
@@ -357,12 +356,6 @@ class TypedIntTable {
 
 using std::vector;
 
-double get_usertime() {
-  struct rusage usage;
-  getrusage(RUSAGE_SELF, &usage);
-  return usage.ru_utime.tv_sec + (usage.ru_utime.tv_usec / 1000000.0);
-}
-
 TEST(Table, StringTable) {
   vector<std::string> keys;
   keys.push_back("google.protobuf.FileDescriptorSet");
diff --git a/upb/util/BUILD b/upb/util/BUILD
index 0270ec8793..be57ce4671 100644
--- a/upb/util/BUILD
+++ b/upb/util/BUILD
@@ -115,6 +115,11 @@ cc_library(
 cc_test(
     name = "compare_test",
     srcs = ["compare_test.cc"],
+    # TODO(b/259158757): fix this test on Windows.
+    target_compatible_with = select({
+        "@platforms//os:windows": ["//third_party/bazel_platforms:incompatible"],
+        "//conditions:default": [],
+    }),
     deps = [
         ":compare",
         "//:wire_internal",
diff --git a/upbc/BUILD b/upbc/BUILD
index aaee51414f..38d1e1ae0c 100644
--- a/upbc/BUILD
+++ b/upbc/BUILD
@@ -176,6 +176,10 @@ cc_binary(
         "subprocess.h",
     ],
     copts = UPB_DEFAULT_CPPOPTS,
+    target_compatible_with = select({
+        "@platforms//os:windows": ["//third_party/bazel_platforms:incompatible"],
+        "//conditions:default": [],
+    }),
     visibility = ["//visibility:public"],
     deps = [
         ":code_generator_request_upb_proto",