diff --git a/homeassistant/components/input_datetime/__init__.py b/homeassistant/components/input_datetime/__init__.py
index 84a7fb89fe1..2713eef17f8 100644
--- a/homeassistant/components/input_datetime/__init__.py
+++ b/homeassistant/components/input_datetime/__init__.py
@@ -81,6 +81,30 @@ def has_date_or_time(conf):
     raise vol.Invalid("Entity needs at least a date or a time")
 
 
+def valid_initial(conf):
+    """Check the initial value is valid."""
+    initial = conf.get(CONF_INITIAL)
+    if not initial:
+        return conf
+
+    if conf[CONF_HAS_DATE] and conf[CONF_HAS_TIME]:
+        parsed_value = dt_util.parse_datetime(initial)
+        if parsed_value is not None:
+            return conf
+        raise vol.Invalid(f"Initial value '{initial}' can't be parsed as a datetime")
+
+    if conf[CONF_HAS_DATE]:
+        parsed_value = dt_util.parse_date(initial)
+        if parsed_value is not None:
+            return conf
+        raise vol.Invalid(f"Initial value '{initial}' can't be parsed as a date")
+
+    parsed_value = dt_util.parse_time(initial)
+    if parsed_value is not None:
+        return conf
+    raise vol.Invalid(f"Initial value '{initial}' can't be parsed as a time")
+
+
 CONFIG_SCHEMA = vol.Schema(
     {
         DOMAIN: cv.schema_with_slug_keys(
@@ -93,6 +117,7 @@ CONFIG_SCHEMA = vol.Schema(
                     vol.Optional(CONF_INITIAL): cv.string,
                 },
                 has_date_or_time,
+                valid_initial,
             )
         )
     },
diff --git a/tests/components/input_datetime/test_init.py b/tests/components/input_datetime/test_init.py
index 39497e1164c..0a968caf67f 100644
--- a/tests/components/input_datetime/test_init.py
+++ b/tests/components/input_datetime/test_init.py
@@ -744,3 +744,30 @@ async def test_timestamp(hass):
 
     finally:
         dt_util.set_default_time_zone(ORIG_TIMEZONE)
+
+
+@pytest.mark.parametrize(
+    "config, error",
+    [
+        (
+            {"has_time": True, "has_date": True, "initial": "abc"},
+            "'abc' can't be parsed as a datetime",
+        ),
+        (
+            {"has_time": False, "has_date": True, "initial": "abc"},
+            "'abc' can't be parsed as a date",
+        ),
+        (
+            {"has_time": True, "has_date": False, "initial": "abc"},
+            "'abc' can't be parsed as a time",
+        ),
+    ],
+)
+async def test_invalid_initial(hass, caplog, config, error):
+    """Test configuration is rejected if the initial value is invalid."""
+    assert not await async_setup_component(
+        hass,
+        DOMAIN,
+        {DOMAIN: {"test_date": config}},
+    )
+    assert error in caplog.text