diff --git a/.strict-typing b/.strict-typing
index 39e03820582..f7a02feec67 100644
--- a/.strict-typing
+++ b/.strict-typing
@@ -388,6 +388,7 @@ homeassistant.components.switchbot_cloud.*
 homeassistant.components.switcher_kis.*
 homeassistant.components.synology_dsm.*
 homeassistant.components.system_health.*
+homeassistant.components.system_log.*
 homeassistant.components.systemmonitor.*
 homeassistant.components.tag.*
 homeassistant.components.tailscale.*
diff --git a/homeassistant/components/system_log/__init__.py b/homeassistant/components/system_log/__init__.py
index fab2b7ee291..3ede14a2ad6 100644
--- a/homeassistant/components/system_log/__init__.py
+++ b/homeassistant/components/system_log/__init__.py
@@ -13,10 +13,12 @@ import voluptuous as vol
 from homeassistant import __path__ as HOMEASSISTANT_PATH
 from homeassistant.components import websocket_api
 from homeassistant.const import EVENT_HOMEASSISTANT_CLOSE
-from homeassistant.core import HomeAssistant, ServiceCall, callback
+from homeassistant.core import Event, HomeAssistant, ServiceCall, callback
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.typing import ConfigType
 
+KeyType = tuple[str, tuple[str, int], str | None]
+
 CONF_MAX_ENTRIES = "max_entries"
 CONF_FIRE_EVENT = "fire_event"
 CONF_MESSAGE = "message"
@@ -60,7 +62,7 @@ SERVICE_WRITE_SCHEMA = vol.Schema(
 
 
 def _figure_out_source(
-    record: logging.LogRecord, paths_re: re.Pattern
+    record: logging.LogRecord, paths_re: re.Pattern[str]
 ) -> tuple[str, int]:
     """Figure out where a log message came from."""
     # If a stack trace exists, extract file names from the entire call stack.
@@ -184,7 +186,7 @@ class LogEntry:
         self.count = 1
         self.key = (self.name, source, self.root_cause)
 
-    def to_dict(self):
+    def to_dict(self) -> dict[str, Any]:
         """Convert object into dict to maintain backward compatibility."""
         return {
             "name": self.name,
@@ -198,10 +200,10 @@ class LogEntry:
         }
 
 
-class DedupStore(OrderedDict):
+class DedupStore(OrderedDict[KeyType, LogEntry]):
     """Data store to hold max amount of deduped entries."""
 
-    def __init__(self, maxlen=50):
+    def __init__(self, maxlen: int = 50) -> None:
         """Initialize a new DedupStore."""
         super().__init__()
         self.maxlen = maxlen
@@ -227,7 +229,7 @@ class DedupStore(OrderedDict):
             # Removes the first record which should also be the oldest
             self.popitem(last=False)
 
-    def to_list(self):
+    def to_list(self) -> list[dict[str, Any]]:
         """Return reversed list of log entries - LIFO."""
         return [value.to_dict() for value in reversed(self.values())]
 
@@ -236,7 +238,11 @@ class LogErrorHandler(logging.Handler):
     """Log handler for error messages."""
 
     def __init__(
-        self, hass: HomeAssistant, maxlen: int, fire_event: bool, paths_re: re.Pattern
+        self,
+        hass: HomeAssistant,
+        maxlen: int,
+        fire_event: bool,
+        paths_re: re.Pattern[str],
     ) -> None:
         """Initialize a new LogErrorHandler."""
         super().__init__()
@@ -276,7 +282,7 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     hass.data[DOMAIN] = handler
 
     @callback
-    def _async_stop_handler(_) -> None:
+    def _async_stop_handler(_: Event) -> None:
         """Cleanup handler."""
         logging.root.removeHandler(handler)
         del hass.data[DOMAIN]
diff --git a/mypy.ini b/mypy.ini
index e349f5d83fc..f3be41c3036 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -3642,6 +3642,16 @@ disallow_untyped_defs = true
 warn_return_any = true
 warn_unreachable = true
 
+[mypy-homeassistant.components.system_log.*]
+check_untyped_defs = true
+disallow_incomplete_defs = true
+disallow_subclassing_any = true
+disallow_untyped_calls = true
+disallow_untyped_decorators = true
+disallow_untyped_defs = true
+warn_return_any = true
+warn_unreachable = true
+
 [mypy-homeassistant.components.systemmonitor.*]
 check_untyped_defs = true
 disallow_incomplete_defs = true