diff --git a/httpcore/client.py b/httpcore/client.py
index cb8ead9fbd..d4dcd33f16 100644
--- a/httpcore/client.py
+++ b/httpcore/client.py
@@ -31,6 +31,7 @@
 class AsyncClient:
     def __init__(
         self,
+        base_url: URLTypes = None,
         ssl: SSLConfig = DEFAULT_SSL_CONFIG,
         timeout: TimeoutConfig = DEFAULT_TIMEOUT_CONFIG,
         pool_limits: PoolLimits = DEFAULT_POOL_LIMITS,
@@ -46,6 +47,8 @@ def __init__(
         self.max_redirects = max_redirects
         self.dispatch = dispatch
 
+        self.base_url = None if base_url is None else URL(base_url)
+
     async def get(
         self,
         url: URLTypes,
@@ -221,6 +224,10 @@ async def request(
         ssl: SSLConfig = None,
         timeout: TimeoutConfig = None,
     ) -> Response:
+
+        if self.base_url is not None:
+            url = URL(url, allow_relative=True).resolve_with(self.base_url)
+
         request = Request(
             method, url, data=data, query_params=query_params, headers=headers
         )
@@ -375,6 +382,7 @@ async def __aexit__(
 class Client:
     def __init__(
         self,
+        base_url: URLTypes = None,
         ssl: SSLConfig = DEFAULT_SSL_CONFIG,
         timeout: TimeoutConfig = DEFAULT_TIMEOUT_CONFIG,
         pool_limits: PoolLimits = DEFAULT_POOL_LIMITS,
@@ -382,8 +390,11 @@ def __init__(
         dispatch: Dispatcher = None,
         backend: ConcurrencyBackend = None,
     ) -> None:
+        self.base_url = None if base_url is None else URL(base_url)
+
         self._client = AsyncClient(
             ssl=ssl,
+            base_url=base_url,
             timeout=timeout,
             pool_limits=pool_limits,
             max_redirects=max_redirects,
@@ -405,6 +416,10 @@ def request(
         ssl: SSLConfig = None,
         timeout: TimeoutConfig = None,
     ) -> SyncResponse:
+
+        if self.base_url is not None:
+            url = URL(url, allow_relative=True).resolve_with(self.base_url)
+
         request = Request(
             method, url, data=data, query_params=query_params, headers=headers
         )
diff --git a/tests/client/test_async_client.py b/tests/client/test_async_client.py
index 27602d12d6..6755258c92 100644
--- a/tests/client/test_async_client.py
+++ b/tests/client/test_async_client.py
@@ -15,6 +15,16 @@ async def test_get(server):
     assert repr(response) == "<Response(200, 'OK')>"
 
 
+@pytest.mark.asyncio
+async def test_get_base_url(server):
+    base_url = "http://127.0.0.1:8000/"
+    async with httpcore.AsyncClient(base_url=base_url) as client:
+        response = await client.get("/hello")
+    assert response.status_code == 200
+    assert response.text == "Hello, world!"
+    assert str(response.url) == "http://127.0.0.1:8000/hello"
+
+
 @pytest.mark.asyncio
 async def test_post(server):
     url = "http://127.0.0.1:8000/"
diff --git a/tests/client/test_client.py b/tests/client/test_client.py
index 820efec175..d49833701c 100644
--- a/tests/client/test_client.py
+++ b/tests/client/test_client.py
@@ -40,6 +40,16 @@ def test_get(server):
     assert repr(response) == "<Response(200, 'OK')>"
 
 
+@threadpool
+def test_get_base_url(server):
+    base_url = "http://127.0.0.1:8000/"
+    with httpcore.Client(base_url=base_url) as client:
+        response = client.get("/hello")
+    assert response.status_code == 200
+    assert response.text == "Hello, world!"
+    assert str(response.url) == "http://127.0.0.1:8000/hello"
+
+
 @threadpool
 def test_post(server):
     with httpcore.Client() as http: