diff --git a/homeassistant/components/script/__init__.py b/homeassistant/components/script/__init__.py
index c0d79c446bb..1af553165bd 100644
--- a/homeassistant/components/script/__init__.py
+++ b/homeassistant/components/script/__init__.py
@@ -18,11 +18,13 @@ from homeassistant.const import (
     ATTR_MODE,
     ATTR_NAME,
     CONF_ALIAS,
+    CONF_DEFAULT,
     CONF_DESCRIPTION,
     CONF_ICON,
     CONF_MODE,
     CONF_NAME,
     CONF_PATH,
+    CONF_SELECTOR,
     CONF_SEQUENCE,
     CONF_VARIABLES,
     SERVICE_RELOAD,
@@ -58,6 +60,7 @@ from homeassistant.helpers.script import (
     ScriptRunResult,
     script_stack_cv,
 )
+from homeassistant.helpers.selector import selector
 from homeassistant.helpers.service import async_set_service_schema
 from homeassistant.helpers.trace import trace_get, trace_path
 from homeassistant.helpers.typing import ConfigType
@@ -71,6 +74,7 @@ from .const import (
     ATTR_LAST_TRIGGERED,
     ATTR_VARIABLES,
     CONF_FIELDS,
+    CONF_REQUIRED,
     CONF_TRACE,
     DOMAIN,
     ENTITY_ID_FORMAT,
@@ -730,11 +734,40 @@ class ScriptEntity(BaseScriptEntity, RestoreEntity):
 
         unique_id = self.unique_id
         hass = self.hass
+
+        service_schema = {}
+        for field_name, field_info in self.fields.items():
+            key_cls = vol.Required if field_info[CONF_REQUIRED] else vol.Optional
+            key_kwargs = {}
+            if CONF_DEFAULT in field_info:
+                key_kwargs["default"] = field_info[CONF_DEFAULT]
+
+            if CONF_SELECTOR in field_info:
+                validator: Any = selector(field_info[CONF_SELECTOR])
+
+                # Default values need to match the validator.
+                # When they don't match, we will not enforce validation
+                if CONF_DEFAULT in field_info:
+                    try:
+                        validator(field_info[CONF_DEFAULT])
+                    except vol.Invalid:
+                        logging.getLogger(f"{__name__}.{self._attr_unique_id}").warning(
+                            "Field %s has invalid default value %s",
+                            field_name,
+                            field_info[CONF_DEFAULT],
+                        )
+                        validator = cv.match_all
+
+            else:
+                validator = cv.match_all
+
+            service_schema[key_cls(field_name, **key_kwargs)] = validator
+
         hass.services.async_register(
             DOMAIN,
             unique_id,
             self._service_handler,
-            schema=SCRIPT_SERVICE_SCHEMA,
+            schema=vol.Schema(service_schema, extra=vol.ALLOW_EXTRA),
             supports_response=SupportsResponse.OPTIONAL,
         )
 
diff --git a/tests/components/script/test_init.py b/tests/components/script/test_init.py
index a5eda3757a9..96ac73438ea 100644
--- a/tests/components/script/test_init.py
+++ b/tests/components/script/test_init.py
@@ -6,6 +6,7 @@ from typing import Any
 from unittest.mock import ANY, Mock, patch
 
 import pytest
+import voluptuous as vol
 
 from homeassistant.components import script
 from homeassistant.components.script import DOMAIN, EVENT_SCRIPT_STARTED, ScriptEntity
@@ -48,6 +49,7 @@ import homeassistant.util.dt as dt_util
 from tests.common import (
     MockConfigEntry,
     MockUser,
+    async_capture_events,
     async_fire_time_changed,
     async_mock_service,
     mock_restore_cache,
@@ -557,6 +559,101 @@ async def test_reload_unchanged_script(
         assert len(calls) == 2
 
 
+async def test_service_schema(
+    hass: HomeAssistant, caplog: pytest.LogCaptureFixture
+) -> None:
+    """Test that service schema are defined correctly."""
+    events = async_capture_events(hass, "test_event")
+
+    assert await async_setup_component(
+        hass,
+        "script",
+        {
+            "script": {
+                "test": {
+                    "fields": {
+                        "param_with_default": {
+                            "default": "default_value",
+                        },
+                        "required_param": {
+                            "required": True,
+                        },
+                        "selector_param": {
+                            "selector": {
+                                "select": {
+                                    "options": [
+                                        "one",
+                                        "two",
+                                    ]
+                                }
+                            }
+                        },
+                        "invalid_default": {
+                            "default": "invalid-value",
+                            "selector": {"number": {"min": 0, "max": 2}},
+                        },
+                    },
+                    "sequence": [
+                        {
+                            "event": "test_event",
+                            "event_data": {
+                                "param_with_default": "{{ param_with_default }}",
+                                "required_param": "{{ required_param }}",
+                                "selector_param": "{{ selector_param | default('not_set') }}",
+                                "invalid_default": "{{ invalid_default }}",
+                            },
+                        }
+                    ],
+                }
+            }
+        },
+    )
+
+    assert (
+        "Field invalid_default has invalid default value invalid-value" in caplog.text
+    )
+
+    await hass.services.async_call(
+        DOMAIN,
+        "test",
+        {"required_param": "required_value"},
+        blocking=True,
+    )
+    assert len(events) == 1
+    assert events[0].data["param_with_default"] == "default_value"
+    assert events[0].data["required_param"] == "required_value"
+    assert events[0].data["selector_param"] == "not_set"
+    assert events[0].data["invalid_default"] == "invalid-value"
+
+    with pytest.raises(vol.Invalid):
+        await hass.services.async_call(
+            DOMAIN,
+            "test",
+            {
+                "required_param": "required_value",
+                "selector_param": "invalid_value",
+            },
+            blocking=True,
+        )
+
+    await hass.services.async_call(
+        DOMAIN,
+        "test",
+        {
+            "param_with_default": "service_set_value",
+            "required_param": "required_value",
+            "selector_param": "one",
+            "invalid_default": "another-value",
+        },
+        blocking=True,
+    )
+    assert len(events) == 2
+    assert events[1].data["param_with_default"] == "service_set_value"
+    assert events[1].data["required_param"] == "required_value"
+    assert events[1].data["selector_param"] == "one"
+    assert events[1].data["invalid_default"] == "another-value"
+
+
 async def test_service_descriptions(hass: HomeAssistant) -> None:
     """Test that service descriptions are loaded and reloaded correctly."""
     # Test 1: has "description" but no "fields"