diff --git a/.github/workflows/test-suite.yml b/.github/workflows/test-suite.yml
index 0bb570cedb..f968a437ef 100644
--- a/.github/workflows/test-suite.yml
+++ b/.github/workflows/test-suite.yml
@@ -7,13 +7,18 @@ on:
   pull_request:
     branches: ["master"]
 
+defaults:
+  run:
+    shell: bash
+
 jobs:
   tests:
-    name: "Python ${{ matrix.python-version }}"
-    runs-on: "ubuntu-latest"
+    name: "Python ${{ matrix.python-version }} (${{ matrix.os }})"
+    runs-on: "${{ matrix.os }}-latest"
 
     strategy:
       matrix:
+        os: ["ubuntu", "windows"]
         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
 
     steps:
@@ -32,3 +37,4 @@ jobs:
         run: "scripts/test"
       - name: "Enforce coverage"
         run: "scripts/coverage"
+        if: "matrix.os == 'ubuntu'"
diff --git a/tests/client/test_async_client.py b/tests/client/test_async_client.py
index 8d7eaa3c58..2e7025ebf3 100644
--- a/tests/client/test_async_client.py
+++ b/tests/client/test_async_client.py
@@ -18,7 +18,9 @@ async def test_get(server):
     assert response.http_version == "HTTP/1.1"
     assert response.headers
     assert repr(response) == "<Response [200 OK]>"
-    assert response.elapsed > timedelta(seconds=0)
+    # time related tests are flaky on windows
+    # Sanity test the property access and return type.
+    assert response.elapsed >= timedelta(seconds=0)
 
 
 @pytest.mark.parametrize(
diff --git a/tests/test_multipart.py b/tests/test_multipart.py
index 764f85a253..9e023cf2bc 100644
--- a/tests/test_multipart.py
+++ b/tests/test_multipart.py
@@ -3,6 +3,7 @@
 import io
 import tempfile
 import typing
+from pathlib import Path
 
 import pytest
 
@@ -371,10 +372,15 @@ def test_multipart_encode_files_raises_exception_with_StringIO_content() -> None
         httpx.Request("POST", url, data={}, files=files)  # type: ignore
 
 
-def test_multipart_encode_files_raises_exception_with_text_mode_file() -> None:
+def test_multipart_encode_files_raises_exception_with_text_mode_file(
+    tmp_path: Path,
+) -> None:
     url = "https://www.example.com"
-    with tempfile.TemporaryFile(mode="w") as upload:
-        files = {"file": ("test.txt", upload, "text/plain")}
+    # TemporaryFiles are always binary mode on windows.
+    # For this test case where we need a text-mode file.
+    tmp_path.joinpath("test.txt").write_text("content")
+    with tmp_path.joinpath("test.txt").open() as temp:
+        files = {"file": ("test.txt", temp, "text/plain")}
         with pytest.raises(TypeError):
             httpx.Request("POST", url, data={}, files=files)  # type: ignore
 
diff --git a/tests/test_timeouts.py b/tests/test_timeouts.py
index 666cc8e376..9cd472edc8 100644
--- a/tests/test_timeouts.py
+++ b/tests/test_timeouts.py
@@ -1,3 +1,5 @@
+import sys
+
 import pytest
 
 import httpx
@@ -12,6 +14,9 @@ async def test_read_timeout(server):
             await client.get(server.url.copy_with(path="/slow_response"))
 
 
+@pytest.mark.skipif(
+    sys.platform == "win32", reason="time related tests are flaky on win32"
+)
 @pytest.mark.anyio
 async def test_write_timeout(server):
     timeout = httpx.Timeout(None, write=1e-6)
diff --git a/tests/test_utils.py b/tests/test_utils.py
index f98a18f2cd..a334161897 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -2,6 +2,7 @@
 import logging
 import os
 import random
+import sys
 
 import certifi
 import pytest
@@ -122,6 +123,7 @@ def test_logging_redirect_chain(server, caplog):
     ]
 
 
+@pytest.mark.skipif(sys.platform == "win32", reason="os path sep escaped on windows")
 def test_logging_ssl(caplog):
     caplog.set_level(logging.DEBUG)
     with httpx.Client():
@@ -155,7 +157,9 @@ def test_get_ssl_cert_file():
     os.environ["SSL_CERT_FILE"] = str(TESTS_DIR / "test_utils.py")
     # SSL_CERT_FILE is correctly set, SSL_CERT_DIR is not set.
     ca_bundle = get_ca_bundle_from_env()
-    assert ca_bundle is not None and ca_bundle.endswith("tests/test_utils.py")
+    assert ca_bundle is not None and ca_bundle.endswith(
+        os.path.join("tests", "test_utils.py")
+    )
 
     os.environ["SSL_CERT_FILE"] = "wrongfile"
     # SSL_CERT_FILE is set with wrong file,  SSL_CERT_DIR is not set.
@@ -170,7 +174,9 @@ def test_get_ssl_cert_file():
     os.environ["SSL_CERT_FILE"] = str(TESTS_DIR / "test_utils.py")
     # Two environments is correctly set.
     ca_bundle = get_ca_bundle_from_env()
-    assert ca_bundle is not None and ca_bundle.endswith("tests/test_utils.py")
+    assert ca_bundle is not None and ca_bundle.endswith(
+        os.path.join("tests", "test_utils.py")
+    )
 
     os.environ["SSL_CERT_FILE"] = "wrongfile"
     # Two environments is set but SSL_CERT_FILE is not a file.