diff --git a/esphome/components/mipi_spi/display.py b/esphome/components/mipi_spi/display.py
index 6aa98e3f66..42c7ec2224 100644
--- a/esphome/components/mipi_spi/display.py
+++ b/esphome/components/mipi_spi/display.py
@@ -279,6 +279,10 @@ def _final_validate(config):
 
     from esphome.components.lvgl import DOMAIN as LVGL_DOMAIN
 
+    if config[CONF_BUS_MODE] == TYPE_SINGLE:
+        spi.final_validate_device_schema(DOMAIN, require_miso=False, require_mosi=True)(
+            config
+        )
     if not requires_buffer(config) and LVGL_DOMAIN not in global_config:
         # If no drawing methods are configured, and LVGL is not enabled, show a test card
         config[CONF_SHOW_TEST_CARD] = True
@@ -286,7 +290,7 @@ def _final_validate(config):
     if PSRAM_DOMAIN not in global_config and CONF_BUFFER_SIZE not in config:
         # If PSRAM is not enabled, choose a small buffer size by default
         if not requires_buffer(config):
-            return config  # No buffer needed, so no need to set a buffer size
+            return  # No need to pick a size
         color_depth = get_color_depth(config)
         frac = denominator(config)
         width, height, _offset_width, _offset_height = model.get_dimensions(config)
@@ -298,8 +302,6 @@ def _final_validate(config):
             x for x in range(2, 17) if fraction >= 1 / x
         )
 
-    return config
-
 
 FINAL_VALIDATE_SCHEMA = _final_validate
 
diff --git a/tests/component_tests/mipi_spi/conftest.py b/tests/component_tests/mipi_spi/conftest.py
index eddf0987d0..082a9e55f2 100644
--- a/tests/component_tests/mipi_spi/conftest.py
+++ b/tests/component_tests/mipi_spi/conftest.py
@@ -1,6 +1,7 @@
 """Tests for mpip_spi configuration validation."""
 
 from collections.abc import Callable, Generator
+from unittest import mock
 
 import pytest
 
@@ -12,6 +13,16 @@ from esphome.core import CORE
 from esphome.pins import gpio_pin_schema
 
 
+@pytest.fixture(autouse=True)
+def mock_spi_final_validate():
+    """Mock spi.final_validate_device_schema since unit tests have no real SPI bus config."""
+    with mock.patch(
+        "esphome.components.spi.final_validate_device_schema",
+        return_value=lambda config: None,
+    ):
+        yield
+
+
 @pytest.fixture
 def choose_variant_with_pins() -> Generator[Callable[[list], None]]:
     """
diff --git a/tests/component_tests/mipi_spi/test_display_metadata.py b/tests/component_tests/mipi_spi/test_display_metadata.py
index ab42a75694..c11c7816e4 100644
--- a/tests/component_tests/mipi_spi/test_display_metadata.py
+++ b/tests/component_tests/mipi_spi/test_display_metadata.py
@@ -25,7 +25,9 @@ from tests.component_tests.types import SetCoreConfigCallable
 
 def validated_config(config):
     """Run schema + final validation and return the validated config."""
-    return FINAL_VALIDATE_SCHEMA(CONFIG_SCHEMA(config))
+    config = CONFIG_SCHEMA(config)
+    FINAL_VALIDATE_SCHEMA(config)
+    return config
 
 
 def test_metadata_native_quad_default_test_card(