diff --git a/src/openai/lib/_tools.py b/src/openai/lib/_tools.py
index 4070ad63bb..6b6419b898 100644
--- a/src/openai/lib/_tools.py
+++ b/src/openai/lib/_tools.py
@@ -1,14 +1,43 @@
 from __future__ import annotations
 
-from typing import Any, Dict, cast
+from typing import Any, Dict, Iterable, List, cast
 
 import pydantic
 
 from ._pydantic import to_strict_json_schema
+from .._types import Omit
+from .._utils import is_given
 from ..types.chat import ChatCompletionFunctionToolParam
 from ..types.shared_params import FunctionDefinition
 from ..types.responses.function_tool_param import FunctionToolParam as ResponsesFunctionToolParam
 
+_WEB_SEARCH_TOOL_TYPES = frozenset(
+    {"web_search", "web_search_2025_08_26", "web_search_preview", "web_search_preview_2025_03_11"}
+)
+
+
+def _apply_web_search_default_location_tools(
+    tools: Iterable[Any] | Omit,
+) -> Iterable[Any] | Omit:
+    """For web_search tools that lack user_location, inject user_location with type='approximate'.
+
+    This prevents the server from defaulting to a US-based location when no
+    user_location is specified, which is unexpected behavior for developers
+    outside the US.
+    """
+    if not is_given(tools):
+        return tools
+
+    result: List[Any] = []
+    changed = False
+    for tool in tools:
+        if isinstance(tool, dict) and tool.get("type") in _WEB_SEARCH_TOOL_TYPES and "user_location" not in tool:
+            tool = {**tool, "user_location": {"type": "approximate"}}
+            changed = True
+        result.append(tool)
+
+    return result if changed else tools
+
 
 class PydanticFunctionTool(Dict[str, Any]):
     """Dictionary wrapper so we can pass the given base model
diff --git a/src/openai/resources/responses/responses.py b/src/openai/resources/responses/responses.py
index 48705098cc..5a089f4da5 100644
--- a/src/openai/resources/responses/responses.py
+++ b/src/openai/resources/responses/responses.py
@@ -44,7 +44,11 @@
     AsyncInputItemsWithStreamingResponse,
 )
 from ..._streaming import Stream, AsyncStream
-from ...lib._tools import PydanticFunctionTool, ResponsesPydanticFunctionTool
+from ...lib._tools import (
+    PydanticFunctionTool,
+    ResponsesPydanticFunctionTool,
+    _apply_web_search_default_location_tools,
+)
 from .input_tokens import (
     InputTokens,
     AsyncInputTokens,
@@ -942,7 +946,7 @@ def create(
                     "temperature": temperature,
                     "text": text,
                     "tool_choice": tool_choice,
-                    "tools": tools,
+                    "tools": _apply_web_search_default_location_tools(tools),
                     "top_logprobs": top_logprobs,
                     "top_p": top_p,
                     "truncation": truncation,
@@ -1256,7 +1260,7 @@ def parser(raw_response: Response) -> ParsedResponse[TextFormatT]:
                     "temperature": temperature,
                     "text": text,
                     "tool_choice": tool_choice,
-                    "tools": tools,
+                    "tools": _apply_web_search_default_location_tools(tools),
                     "top_logprobs": top_logprobs,
                     "top_p": top_p,
                     "truncation": truncation,
@@ -2623,7 +2627,7 @@ async def create(
                     "temperature": temperature,
                     "text": text,
                     "tool_choice": tool_choice,
-                    "tools": tools,
+                    "tools": _apply_web_search_default_location_tools(tools),
                     "top_logprobs": top_logprobs,
                     "top_p": top_p,
                     "truncation": truncation,
@@ -2941,7 +2945,7 @@ def parser(raw_response: Response) -> ParsedResponse[TextFormatT]:
                     "temperature": temperature,
                     "text": text,
                     "tool_choice": tool_choice,
-                    "tools": tools,
+                    "tools": _apply_web_search_default_location_tools(tools),
                     "top_logprobs": top_logprobs,
                     "top_p": top_p,
                     "truncation": truncation,
@@ -4597,7 +4601,7 @@ def create(
                         "temperature": temperature,
                         "text": text,
                         "tool_choice": tool_choice,
-                        "tools": tools,
+                        "tools": _apply_web_search_default_location_tools(tools),
                         "top_logprobs": top_logprobs,
                         "top_p": top_p,
                         "truncation": truncation,
@@ -4677,7 +4681,7 @@ async def create(
                         "temperature": temperature,
                         "text": text,
                         "tool_choice": tool_choice,
-                        "tools": tools,
+                        "tools": _apply_web_search_default_location_tools(tools),
                         "top_logprobs": top_logprobs,
                         "top_p": top_p,
                         "truncation": truncation,
diff --git a/tests/lib/test_tools.py b/tests/lib/test_tools.py
new file mode 100644
index 0000000000..8cbf8ae302
--- /dev/null
+++ b/tests/lib/test_tools.py
@@ -0,0 +1,84 @@
+from __future__ import annotations
+
+from openai._types import Omit, omit
+from openai.lib._tools import _apply_web_search_default_location_tools
+
+
+class TestApplyWebSearchDefaultLocationTools:
+    """Tests for _apply_web_search_default_location_tools."""
+
+    def test_no_tools_returns_omit(self) -> None:
+        """When tools is Omit (not given), return it unchanged."""
+        result = _apply_web_search_default_location_tools(omit)
+        assert result is omit
+
+    def test_empty_tools_list(self) -> None:
+        """An empty list of tools should be returned unchanged."""
+        tools: list = []
+        result = _apply_web_search_default_location_tools(tools)
+        assert result is tools  # same reference, no changes
+
+    def test_non_web_search_tools_unchanged(self) -> None:
+        """Tools that are not web_search should not be modified."""
+        tools = [
+            {"type": "function", "function": {"name": "my_func"}},
+            {"type": "code_interpreter"},
+        ]
+        result = _apply_web_search_default_location_tools(tools)
+        assert result is tools  # same reference, no changes
+
+    def test_web_search_injects_user_location(self) -> None:
+        """web_search without user_location should get one injected."""
+        tools = [{"type": "web_search"}]
+        result = _apply_web_search_default_location_tools(tools)
+        assert result is not tools  # new list created
+        assert result[0]["user_location"] == {"type": "approximate"}
+        assert result[0]["type"] == "web_search"
+
+    def test_web_search_with_existing_user_location_unchanged(self) -> None:
+        """web_search that already has user_location should not be overridden."""
+        existing_loc = {"type": "approximate", "city": "London", "country": "GB"}
+        tools = [{"type": "web_search", "user_location": existing_loc}]
+        result = _apply_web_search_default_location_tools(tools)
+        assert result is tools  # same reference, no changes needed
+        assert result[0]["user_location"] is existing_loc
+
+    def test_web_search_2025_08_26_injects(self) -> None:
+        tools = [{"type": "web_search_2025_08_26"}]
+        result = _apply_web_search_default_location_tools(tools)
+        assert result[0]["user_location"] == {"type": "approximate"}
+
+    def test_web_search_preview_injects(self) -> None:
+        tools = [{"type": "web_search_preview"}]
+        result = _apply_web_search_default_location_tools(tools)
+        assert result[0]["user_location"] == {"type": "approximate"}
+
+    def test_web_search_preview_2025_03_11_injects(self) -> None:
+        tools = [{"type": "web_search_preview_2025_03_11"}]
+        result = _apply_web_search_default_location_tools(tools)
+        assert result[0]["user_location"] == {"type": "approximate"}
+
+    def test_mixed_tools_only_web_search_modified(self) -> None:
+        """When mixing web_search and non-web-search tools, only web_search gets modified."""
+        func_tool = {"type": "function", "function": {"name": "foo"}}
+        ws_tool = {"type": "web_search"}
+        tools = [func_tool, ws_tool]
+        result = _apply_web_search_default_location_tools(tools)
+        # function tool is unchanged
+        assert result[0] is func_tool
+        # web_search tool is a new dict with user_location injected
+        assert result[1]["user_location"] == {"type": "approximate"}
+        assert result[1]["type"] == "web_search"
+
+    def test_web_search_preserves_other_keys(self) -> None:
+        """Injecting user_location should not drop other keys on the tool dict."""
+        tools = [{"type": "web_search", "extra_key": "value"}]
+        result = _apply_web_search_default_location_tools(tools)
+        assert result[0]["extra_key"] == "value"
+        assert result[0]["user_location"] == {"type": "approximate"}
+
+    def test_non_dict_tool_not_modified(self) -> None:
+        """Non-dict tools (e.g. string shorthand) should pass through."""
+        tools = ["web_search"]  # string, not dict
+        result = _apply_web_search_default_location_tools(tools)
+        assert result is tools  # unchanged