diff --git a/esphome/components/debug/sensor.py b/esphome/components/debug/sensor.py
index deea6fd5ed..f7ea07d138 100644
--- a/esphome/components/debug/sensor.py
+++ b/esphome/components/debug/sensor.py
@@ -6,6 +6,7 @@ from esphome.const import (
     CONF_FRAGMENTATION,
     CONF_BLOCK,
     CONF_LOOP_TIME,
+    ENTITY_CATEGORY_DIAGNOSTIC,
     UNIT_MILLISECOND,
     UNIT_PERCENT,
     UNIT_BYTES,
@@ -18,14 +19,34 @@ DEPENDENCIES = ["debug"]
 
 CONFIG_SCHEMA = {
     cv.GenerateID(CONF_DEBUG_ID): cv.use_id(DebugComponent),
-    cv.Optional(CONF_FREE): sensor.sensor_schema(UNIT_BYTES, ICON_COUNTER, 0),
-    cv.Optional(CONF_BLOCK): sensor.sensor_schema(UNIT_BYTES, ICON_COUNTER, 0),
+    cv.Optional(CONF_FREE): sensor.sensor_schema(
+        unit_of_measurement=UNIT_BYTES,
+        icon=ICON_COUNTER,
+        accuracy_decimals=0,
+        entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
+    ),
+    cv.Optional(CONF_BLOCK): sensor.sensor_schema(
+        unit_of_measurement=UNIT_BYTES,
+        icon=ICON_COUNTER,
+        accuracy_decimals=0,
+        entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
+    ),
     cv.Optional(CONF_FRAGMENTATION): cv.All(
         cv.only_on_esp8266,
         cv.require_framework_version(esp8266_arduino=cv.Version(2, 5, 2)),
-        sensor.sensor_schema(UNIT_PERCENT, ICON_COUNTER, 1),
+        sensor.sensor_schema(
+            unit_of_measurement=UNIT_PERCENT,
+            icon=ICON_COUNTER,
+            accuracy_decimals=1,
+            entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
+        ),
+    ),
+    cv.Optional(CONF_LOOP_TIME): sensor.sensor_schema(
+        unit_of_measurement=UNIT_MILLISECOND,
+        icon=ICON_TIMER,
+        accuracy_decimals=0,
+        entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
     ),
-    cv.Optional(CONF_LOOP_TIME): sensor.sensor_schema(UNIT_MILLISECOND, ICON_TIMER, 0),
 }
 
 
diff --git a/esphome/components/debug/text_sensor.py b/esphome/components/debug/text_sensor.py
index f8d1016fbf..11e6354f57 100644
--- a/esphome/components/debug/text_sensor.py
+++ b/esphome/components/debug/text_sensor.py
@@ -1,7 +1,7 @@
 from esphome.components import text_sensor
 import esphome.config_validation as cv
 import esphome.codegen as cg
-from esphome.const import CONF_DEVICE
+from esphome.const import CONF_DEVICE, ENTITY_CATEGORY_DIAGNOSTIC
 
 from . import CONF_DEBUG_ID, DebugComponent
 
@@ -11,7 +11,9 @@ DEPENDENCIES = ["debug"]
 CONFIG_SCHEMA = cv.Schema(
     {
         cv.GenerateID(CONF_DEBUG_ID): cv.use_id(DebugComponent),
-        cv.Optional(CONF_DEVICE): text_sensor.text_sensor_schema(),
+        cv.Optional(CONF_DEVICE): text_sensor.text_sensor_schema(
+            entity_category=ENTITY_CATEGORY_DIAGNOSTIC
+        ),
     }
 )