diff --git a/esphome/core/__init__.py b/esphome/core/__init__.py
index 0d4ddf56d4..476ff1c618 100644
--- a/esphome/core/__init__.py
+++ b/esphome/core/__init__.py
@@ -6,6 +6,9 @@ import os
 import re
 from typing import TYPE_CHECKING
 
+if TYPE_CHECKING:
+    from esphome.address_cache import AddressCache
+
 from esphome.const import (
     CONF_COMMENT,
     CONF_ESPHOME,
@@ -584,7 +587,7 @@ class EsphomeCore:
         # The current component being processed during validation
         self.current_component: str | None = None
         # Address cache for DNS and mDNS lookups from command line arguments
-        self.address_cache: object | None = None
+        self.address_cache: AddressCache | None = None
 
     def reset(self):
         from esphome.pins import PIN_SCHEMA_REGISTRY
diff --git a/esphome/dashboard/web_server.py b/esphome/dashboard/web_server.py
index 767144fd19..ff92fea958 100644
--- a/esphome/dashboard/web_server.py
+++ b/esphome/dashboard/web_server.py
@@ -364,14 +364,16 @@ class EsphomePortCommandWebSocket(EsphomeCommandWebSocket):
                     addresses.extend(sort_ip_addresses(cached))
                     dns_cache_entries[entry.name] = set(cached)
 
-            # Build cache arguments to pass to CLI
+            # Build cache arguments to pass to CLI (normalize hostnames)
             for hostname, addrs in dns_cache_entries.items():
+                normalized = hostname.rstrip(".").lower()
                 cache_args.extend(
-                    ["--dns-lookup-cache", f"{hostname}={','.join(sorted(addrs))}"]
+                    ["--dns-lookup-cache", f"{normalized}={','.join(sorted(addrs))}"]
                 )
             for hostname, addrs in mdns_cache_entries.items():
+                normalized = hostname.rstrip(".").lower()
                 cache_args.extend(
-                    ["--mdns-lookup-cache", f"{hostname}={','.join(sorted(addrs))}"]
+                    ["--mdns-lookup-cache", f"{normalized}={','.join(sorted(addrs))}"]
                 )
 
         if not addresses:
diff --git a/tests/unit_tests/test_main.py b/tests/unit_tests/test_main.py
index ce19f18a1f..a00d8ce43a 100644
--- a/tests/unit_tests/test_main.py
+++ b/tests/unit_tests/test_main.py
@@ -581,3 +581,47 @@ def test_address_cache_get_methods() -> None:
     assert cache.has_cache() is True
     empty_cache = AddressCache()
     assert empty_cache.has_cache() is False
+
+
+def test_address_cache_hostname_normalization() -> None:
+    """Test that hostnames are normalized for cache lookups."""
+    from esphome.address_cache import normalize_hostname
+
+    # Test normalize_hostname function
+    assert normalize_hostname("test.local") == "test.local"
+    assert normalize_hostname("test.local.") == "test.local"
+    assert normalize_hostname("TEST.LOCAL") == "test.local"
+    assert normalize_hostname("TeSt.LoCaL.") == "test.local"
+    assert normalize_hostname("example.com.") == "example.com"
+
+    # Test cache with normalized lookups
+    cache = AddressCache(
+        mdns_cache={"test.local": ["192.168.1.1"]},
+        dns_cache={"example.com": ["10.0.0.1"]},
+    )
+
+    # Should find with different case and trailing dots
+    assert cache.get_mdns_addresses("test.local") == ["192.168.1.1"]
+    assert cache.get_mdns_addresses("TEST.LOCAL") == ["192.168.1.1"]
+    assert cache.get_mdns_addresses("test.local.") == ["192.168.1.1"]
+    assert cache.get_mdns_addresses("TEST.LOCAL.") == ["192.168.1.1"]
+
+    assert cache.get_dns_addresses("example.com") == ["10.0.0.1"]
+    assert cache.get_dns_addresses("EXAMPLE.COM") == ["10.0.0.1"]
+    assert cache.get_dns_addresses("example.com.") == ["10.0.0.1"]
+    assert cache.get_dns_addresses("EXAMPLE.COM.") == ["10.0.0.1"]
+
+    # Test from_cli_args also normalizes
+    cache = AddressCache.from_cli_args(
+        ["TEST.LOCAL.=192.168.1.1"], ["EXAMPLE.COM.=10.0.0.1"]
+    )
+
+    # Should store as normalized
+    assert "test.local" in cache.mdns_cache
+    assert "example.com" in cache.dns_cache
+
+    # Should find with any variation
+    assert cache.get_addresses("test.local") == ["192.168.1.1"]
+    assert cache.get_addresses("TEST.LOCAL.") == ["192.168.1.1"]
+    assert cache.get_addresses("example.com") == ["10.0.0.1"]
+    assert cache.get_addresses("EXAMPLE.COM.") == ["10.0.0.1"]