diff --git a/tests/integration/fixtures/object_id_friendly_name_no_mac_suffix.yaml b/tests/integration/fixtures/object_id_friendly_name_no_mac_suffix.yaml
new file mode 100644
index 0000000000..7a86e37d08
--- /dev/null
+++ b/tests/integration/fixtures/object_id_friendly_name_no_mac_suffix.yaml
@@ -0,0 +1,27 @@
+esphome:
+  name: test-device
+  # friendly_name set but NO MAC suffix
+  # Empty-name entity should use friendly_name for object_id
+  friendly_name: My Friendly Device
+
+host:
+
+api:
+
+logger:
+
+sensor:
+  # Empty name entity - should use friendly_name for object_id
+  # friendly_name = "My Friendly Device" -> object_id = "my_friendly_device"
+  - platform: template
+    name: ""
+    id: sensor_empty_name
+    lambda: return 42.0;
+    update_interval: 60s
+
+  # Named entity for comparison
+  - platform: template
+    name: "Temperature"
+    id: sensor_named
+    lambda: return 43.0;
+    update_interval: 60s
diff --git a/tests/integration/test_object_id_friendly_name_no_mac_suffix.py b/tests/integration/test_object_id_friendly_name_no_mac_suffix.py
new file mode 100644
index 0000000000..40066532e7
--- /dev/null
+++ b/tests/integration/test_object_id_friendly_name_no_mac_suffix.py
@@ -0,0 +1,107 @@
+"""Integration test for object_id with friendly_name but no MAC suffix.
+
+This test covers Branch 4 of the algorithm:
+- Empty name on main device
+- NO MAC suffix enabled
+- friendly_name IS set
+- Result: use friendly_name for object_id
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from esphome.helpers import fnv1_hash_object_id, sanitize, snake_case
+
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+def compute_expected_object_id(name: str) -> str:
+    """Compute expected object_id from name using Python helpers."""
+    return sanitize(snake_case(name))
+
+
+@pytest.mark.asyncio
+async def test_object_id_friendly_name_no_mac_suffix(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test object_id when friendly_name is set but no MAC suffix.
+
+    This covers Branch 4 of the algorithm:
+    - Empty name entity
+    - name_add_mac_suffix = false (or not set)
+    - friendly_name = "My Friendly Device"
+    - Expected: object_id = "my_friendly_device"
+    """
+    async with run_compiled(yaml_config), api_client_connected() as client:
+        device_info = await client.device_info()
+        assert device_info is not None
+
+        # Device name should NOT include MAC suffix
+        assert device_info.name == "test-device"
+
+        # Friendly name should be set
+        assert device_info.friendly_name == "My Friendly Device"
+
+        entities, _ = await client.list_entities_services()
+
+        # Find the empty-name entity
+        empty_name_entities = [e for e in entities if e.name == ""]
+        assert len(empty_name_entities) == 1
+
+        entity = empty_name_entities[0]
+
+        # Should use friendly_name for object_id (Branch 4)
+        expected_object_id = compute_expected_object_id("My Friendly Device")
+        assert expected_object_id == "my_friendly_device"  # Verify our expectation
+        assert entity.object_id == expected_object_id, (
+            f"Expected object_id '{expected_object_id}' from friendly_name, "
+            f"got '{entity.object_id}'"
+        )
+
+        # Hash should match friendly_name
+        expected_hash = fnv1_hash_object_id("My Friendly Device")
+        assert entity.key == expected_hash, (
+            f"Expected hash {expected_hash:#x}, got {entity.key:#x}"
+        )
+
+        # Named entity should work normally
+        named_entities = [e for e in entities if e.name == "Temperature"]
+        assert len(named_entities) == 1
+        assert named_entities[0].object_id == "temperature"
+
+        # Verify the full algorithm from PR summary works for ALL entities
+        # NOTE: `name_add_mac_suffix` needs to be added to DeviceInfoResponse.
+        # For now, we infer it from the device name ending with MAC suffix.
+        mac_suffix = device_info.mac_address.replace(":", "")[-6:].lower()
+        name_add_mac_suffix = device_info.name.endswith(f"-{mac_suffix}")
+
+        # Verify our inference: no MAC suffix in this test
+        assert not name_add_mac_suffix, "Device name should NOT have MAC suffix"
+
+        for entity in entities:
+            if entity.name:
+                name_for_id = entity.name
+            elif name_add_mac_suffix:
+                # MAC suffix enabled: use friendly_name directly (even if empty)
+                name_for_id = device_info.friendly_name
+            elif device_info.friendly_name:
+                # Branch 4: No MAC suffix, but friendly_name is set
+                name_for_id = device_info.friendly_name
+            else:
+                # No MAC suffix, no friendly_name: use device name
+                name_for_id = device_info.name
+
+            computed_object_id = compute_expected_object_id(name_for_id)
+            assert entity.object_id == computed_object_id, (
+                f"Algorithm failed for entity '{entity.name}': "
+                f"expected '{computed_object_id}', got '{entity.object_id}'"
+            )
+
+            computed_hash = fnv1_hash_object_id(name_for_id)
+            assert entity.key == computed_hash, (
+                f"Algorithm hash failed for entity '{entity.name}': "
+                f"expected {computed_hash:#x}, got {entity.key:#x}"
+            )