diff --git a/homeassistant/components/homeassistant/strings.json b/homeassistant/components/homeassistant/strings.json
index 6981bdfe685f..862ac12cefbf 100644
--- a/homeassistant/components/homeassistant/strings.json
+++ b/homeassistant/components/homeassistant/strings.json
@@ -12,6 +12,14 @@
       "title": "The configured currency is no longer in use",
       "description": "The currency {currency} is no longer in use, please reconfigure the currency configuration."
     },
+    "legacy_templates_false": {
+      "title": "`legacy_templates` config key is being removed",
+      "description": "Nothing will change with your templates.\n\nRemove the `legacy_templates` key from the `homeassistant` configuration in your configuration.yaml file and restart Home Assistant to fix this issue."
+    },
+    "legacy_templates_true": {
+      "title": "The support for legacy templates is being removed",
+      "description": "Please do the following steps:\n- Adopt your configuration to support template rendering to native python types.\n- Remove the `legacy_templates` key from the `homeassistant` configuration in your configuration.yaml file.\n- Restart Home Assistant to fix this issue."
+    },
     "python_version": {
       "title": "Support for Python {current_python_version} is being removed",
       "description": "Support for running Home Assistant in the current used Python version {current_python_version} is deprecated and will be removed in Home Assistant {breaks_in_ha_version}. Please upgrade Python to {required_python_version} to prevent your Home Assistant instance from breaking."
diff --git a/homeassistant/config.py b/homeassistant/config.py
index d5b6864c9379..949774d33612 100644
--- a/homeassistant/config.py
+++ b/homeassistant/config.py
@@ -272,6 +272,41 @@ def _raise_issue_if_no_country(hass: HomeAssistant, country: str | None) -> None
     )
 
 
+def _raise_issue_if_legacy_templates(
+    hass: HomeAssistant, legacy_templates: bool | None
+) -> None:
+    # legacy_templates can have the following values:
+    # - None: Using default value (False) -> Delete repair issues
+    # - True: Create repair to adopt templates to new syntax
+    # - False: Create repair to tell user to remove config key
+    if legacy_templates:
+        ir.async_create_issue(
+            hass,
+            "homeassistant",
+            "legacy_templates_true",
+            is_fixable=False,
+            breaks_in_ha_version="2024.7.0",
+            severity=ir.IssueSeverity.WARNING,
+            translation_key="legacy_templates_true",
+        )
+        return
+
+    ir.async_delete_issue(hass, "homeassistant", "legacy_templates_true")
+
+    if legacy_templates is False:
+        ir.async_create_issue(
+            hass,
+            "homeassistant",
+            "legacy_templates_false",
+            is_fixable=False,
+            breaks_in_ha_version="2024.7.0",
+            severity=ir.IssueSeverity.WARNING,
+            translation_key="legacy_templates_false",
+        )
+    else:
+        ir.async_delete_issue(hass, "homeassistant", "legacy_templates_false")
+
+
 def _validate_currency(data: Any) -> Any:
     try:
         return cv.currency(data)
@@ -840,6 +875,7 @@ async def async_process_ha_core_config(hass: HomeAssistant, config: dict) -> Non
         if key in config:
             setattr(hac, attr, config[key])
 
+    _raise_issue_if_legacy_templates(hass, config.get(CONF_LEGACY_TEMPLATES))
     _raise_issue_if_historic_currency(hass, hass.config.currency)
     _raise_issue_if_no_country(hass, hass.config.country)
 
diff --git a/tests/test_config.py b/tests/test_config.py
index 8ec509cd895f..0f6b36d90b5e 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -1980,6 +1980,30 @@ async def test_core_config_schema_no_country(hass: HomeAssistant) -> None:
     assert issue
 
 
+@pytest.mark.parametrize(
+    ("config", "expected_issue"),
+    [
+        ({}, None),
+        ({"legacy_templates": True}, "legacy_templates_true"),
+        ({"legacy_templates": False}, "legacy_templates_false"),
+    ],
+)
+async def test_core_config_schema_legacy_template(
+    hass: HomeAssistant, config: dict[str, Any], expected_issue: str | None
+) -> None:
+    """Test legacy_template core config schema."""
+    await config_util.async_process_ha_core_config(hass, config)
+
+    issue_registry = ir.async_get(hass)
+    for issue_id in {"legacy_templates_true", "legacy_templates_false"}:
+        issue = issue_registry.async_get_issue("homeassistant", issue_id)
+        assert issue if issue_id == expected_issue else not issue
+
+    await config_util.async_process_ha_core_config(hass, {})
+    for issue_id in {"legacy_templates_true", "legacy_templates_false"}:
+        assert not issue_registry.async_get_issue("homeassistant", issue_id)
+
+
 async def test_core_store_no_country(
     hass: HomeAssistant, hass_storage: dict[str, Any]
 ) -> None: