diff --git a/redbot/cogs/filter/filter.py b/redbot/cogs/filter/filter.py
index 318aa1d94..b50e5f336 100644
--- a/redbot/cogs/filter/filter.py
+++ b/redbot/cogs/filter/filter.py
@@ -1,5 +1,6 @@
 import discord
 import re
+from datetime import timezone
 from typing import Union, Set, Literal
 
 from redbot.core import checks, Config, modlog, commands
@@ -339,10 +340,11 @@ class Filter(commands.Cog):
         filter_time = guild_data["filterban_time"]
         user_count = member_data["filter_count"]
         next_reset_time = member_data["next_reset_time"]
+        created_at = message.created_at.replace(tzinfo=timezone.utc)
 
         if filter_count > 0 and filter_time > 0:
-            if message.created_at.timestamp() >= next_reset_time:
-                next_reset_time = message.created_at.timestamp() + filter_time
+            if created_at.timestamp() >= next_reset_time:
+                next_reset_time = created_at.timestamp() + filter_time
                 async with self.config.member(author).all() as member_data:
                     member_data["next_reset_time"] = next_reset_time
                     if user_count > 0:
@@ -361,10 +363,7 @@ class Filter(commands.Cog):
                 if filter_count > 0 and filter_time > 0:
                     user_count += 1
                     await self.config.member(author).filter_count.set(user_count)
-                    if (
-                        user_count >= filter_count
-                        and message.created_at.timestamp() < next_reset_time
-                    ):
+                    if user_count >= filter_count and created_at.timestamp() < next_reset_time:
                         reason = _("Autoban (too many filtered messages.)")
                         try:
                             await guild.ban(author, reason=reason)
@@ -374,7 +373,7 @@ class Filter(commands.Cog):
                             await modlog.create_case(
                                 self.bot,
                                 guild,
-                                message.created_at,
+                                message.created_at.replace(tzinfo=timezone.utc),
                                 "filterban",
                                 author,
                                 guild.me,
diff --git a/redbot/cogs/mod/events.py b/redbot/cogs/mod/events.py
index a9803753a..ee56e582d 100644
--- a/redbot/cogs/mod/events.py
+++ b/redbot/cogs/mod/events.py
@@ -1,5 +1,5 @@
 import logging
-from datetime import datetime
+from datetime import timezone
 from collections import defaultdict, deque
 
 import discord
@@ -60,7 +60,7 @@ class Events(MixinMeta):
                     await modlog.create_case(
                         self.bot,
                         guild,
-                        message.created_at,
+                        message.created_at.replace(tzinfo=timezone.utc),
                         "ban",
                         author,
                         guild.me,
@@ -84,7 +84,7 @@ class Events(MixinMeta):
                     await modlog.create_case(
                         self.bot,
                         guild,
-                        message.created_at,
+                        message.created_at.replace(tzinfo=timezone.utc),
                         "kick",
                         author,
                         guild.me,
@@ -116,7 +116,7 @@ class Events(MixinMeta):
                 await modlog.create_case(
                     self.bot,
                     guild,
-                    message.created_at,
+                    message.created_at.replace(tzinfo=timezone.utc),
                     "warning",
                     author,
                     guild.me,
diff --git a/redbot/cogs/mod/kickban.py b/redbot/cogs/mod/kickban.py
index cfb7be308..4dcd135be 100644
--- a/redbot/cogs/mod/kickban.py
+++ b/redbot/cogs/mod/kickban.py
@@ -1,7 +1,7 @@
 import asyncio
 import contextlib
 import logging
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from typing import Optional, Union
 
 import discord
@@ -120,7 +120,7 @@ class KickBanMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "ban",
                 user,
                 author,
@@ -142,10 +142,11 @@ class KickBanMixin(MixinMeta):
 
                 async with self.config.guild(guild).current_tempbans() as guild_tempbans:
                     for uid in guild_tempbans.copy():
-                        unban_time = datetime.utcfromtimestamp(
-                            await self.config.member_from_ids(guild.id, uid).banned_until()
+                        unban_time = datetime.fromtimestamp(
+                            await self.config.member_from_ids(guild.id, uid).banned_until(),
+                            timezone.utc,
                         )
-                        if datetime.utcnow() > unban_time:  # Time to unban the user
+                        if datetime.now(timezone.utc) > unban_time:  # Time to unban the user
                             queue_entry = (guild.id, uid)
                             try:
                                 await guild.unban(
@@ -228,7 +229,7 @@ class KickBanMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "kick",
                 user,
                 author,
@@ -410,7 +411,7 @@ class KickBanMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "hackban",
                 user_id,
                 author,
@@ -436,7 +437,7 @@ class KickBanMixin(MixinMeta):
         """Temporarily ban a user from this server."""
         guild = ctx.guild
         author = ctx.author
-        unban_time = datetime.utcnow() + duration
+        unban_time = datetime.now(timezone.utc) + duration
 
         if author == user:
             await ctx.send(
@@ -491,7 +492,7 @@ class KickBanMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "tempban",
                 user,
                 author,
@@ -574,7 +575,7 @@ class KickBanMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "softban",
                 user,
                 author,
@@ -621,7 +622,7 @@ class KickBanMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "vkick",
                 member,
                 author,
@@ -660,7 +661,7 @@ class KickBanMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "unban",
                 user,
                 author,
diff --git a/redbot/cogs/mod/mutes.py b/redbot/cogs/mod/mutes.py
index faaab3304..80c3df81d 100644
--- a/redbot/cogs/mod/mutes.py
+++ b/redbot/cogs/mod/mutes.py
@@ -1,4 +1,5 @@
 import asyncio
+from datetime import timezone
 from typing import cast, Optional
 
 import discord
@@ -107,7 +108,7 @@ class MuteMixin(MixinMeta):
         await modlog.create_case(
             self.bot,
             guild,
-            ctx.message.created_at,
+            ctx.message.created_at.replace(tzinfo=timezone.utc),
             "voiceunban",
             user,
             author,
@@ -148,7 +149,7 @@ class MuteMixin(MixinMeta):
         await modlog.create_case(
             self.bot,
             guild,
-            ctx.message.created_at,
+            ctx.message.created_at.replace(tzinfo=timezone.utc),
             "voiceban",
             user,
             author,
@@ -188,7 +189,7 @@ class MuteMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "vmute",
                 user,
                 author,
@@ -232,7 +233,7 @@ class MuteMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "cmute",
                 user,
                 author,
@@ -262,7 +263,7 @@ class MuteMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "smute",
                 user,
                 author,
@@ -305,7 +306,7 @@ class MuteMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "vunmute",
                 user,
                 author,
@@ -349,7 +350,7 @@ class MuteMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "cunmute",
                 user,
                 author,
@@ -383,7 +384,7 @@ class MuteMixin(MixinMeta):
             await modlog.create_case(
                 self.bot,
                 guild,
-                ctx.message.created_at,
+                ctx.message.created_at.replace(tzinfo=timezone.utc),
                 "sunmute",
                 user,
                 author,
diff --git a/redbot/cogs/modlog/modlog.py b/redbot/cogs/modlog/modlog.py
index 0d1979b8e..845a63a69 100644
--- a/redbot/cogs/modlog/modlog.py
+++ b/redbot/cogs/modlog/modlog.py
@@ -1,3 +1,4 @@
+from datetime import timezone
 from typing import Optional, Union
 
 import discord
@@ -181,7 +182,7 @@ class ModLog(commands.Cog):
         to_modify = {"reason": reason}
         if case_obj.moderator != author:
             to_modify["amended_by"] = author
-        to_modify["modified_at"] = ctx.message.created_at.timestamp()
+        to_modify["modified_at"] = ctx.message.created_at.replace(tzinfo=timezone.utc).timestamp()
         await case_obj.edit(to_modify)
         await ctx.send(
             _("Reason for case #{num} has been updated.").format(num=case_obj.case_number)
diff --git a/redbot/cogs/warnings/warnings.py b/redbot/cogs/warnings/warnings.py
index 9e73692ba..413fd7d76 100644
--- a/redbot/cogs/warnings/warnings.py
+++ b/redbot/cogs/warnings/warnings.py
@@ -1,5 +1,6 @@
 import asyncio
 import contextlib
+from datetime import timezone
 from collections import namedtuple
 from copy import copy
 from typing import Union, Optional, Literal
@@ -494,7 +495,7 @@ class Warnings(commands.Cog):
         await modlog.create_case(
             self.bot,
             ctx.guild,
-            ctx.message.created_at,
+            ctx.message.created_at.replace(tzinfo=timezone.utc),
             "warning",
             user,
             ctx.message.author,
@@ -616,7 +617,7 @@ class Warnings(commands.Cog):
         await modlog.create_case(
             self.bot,
             ctx.guild,
-            ctx.message.created_at,
+            ctx.message.created_at.replace(tzinfo=timezone.utc),
             "unwarned",
             member,
             ctx.message.author,
diff --git a/redbot/core/bank.py b/redbot/core/bank.py
index adee5b322..06c745330 100644
--- a/redbot/core/bank.py
+++ b/redbot/core/bank.py
@@ -1,8 +1,8 @@
 from __future__ import annotations
 
 import asyncio
-import datetime
 import logging
+from datetime import datetime, timezone
 from typing import Union, List, Optional, TYPE_CHECKING, Literal
 from functools import wraps
 
@@ -109,7 +109,7 @@ class Account:
 
     This class should ONLY be instantiated by the bank itself."""
 
-    def __init__(self, name: str, balance: int, created_at: datetime.datetime):
+    def __init__(self, name: str, balance: int, created_at: datetime):
         self.name = name
         self.balance = balance
         self.created_at = created_at
@@ -117,25 +117,25 @@ class Account:
 
 def _encoded_current_time() -> int:
     """Get the current UTC time as a timestamp.
-    
+
     Returns
     -------
     int
         The current UTC timestamp.
 
     """
-    now = datetime.datetime.utcnow()
+    now = datetime.now(timezone.utc)
     return _encode_time(now)
 
 
-def _encode_time(time: datetime.datetime) -> int:
+def _encode_time(time: datetime) -> int:
     """Convert a datetime object to a serializable int.
-    
+
     Parameters
     ----------
     time : datetime.datetime
         The datetime to convert.
-        
+
     Returns
     -------
     int
@@ -146,21 +146,21 @@ def _encode_time(time: datetime.datetime) -> int:
     return ret
 
 
-def _decode_time(time: int) -> datetime.datetime:
+def _decode_time(time: int) -> datetime:
     """Convert a timestamp to a datetime object.
-    
+
     Parameters
     ----------
     time : int
         The timestamp to decode.
-        
+
     Returns
     -------
     datetime.datetime
         The datetime object from the timestamp.
 
     """
-    return datetime.datetime.utcfromtimestamp(time)
+    return datetime.utcfromtimestamp(time)
 
 
 async def get_balance(member: discord.Member) -> int:
diff --git a/redbot/core/events.py b/redbot/core/events.py
index fe9866567..9763f96b8 100644
--- a/redbot/core/events.py
+++ b/redbot/core/events.py
@@ -3,10 +3,9 @@ import contextlib
 import platform
 import sys
 import codecs
-import datetime
 import logging
 import traceback
-from datetime import timedelta
+from datetime import datetime, timedelta
 
 import aiohttp
 import discord
@@ -55,7 +54,7 @@ def init_events(bot, cli_flags):
         if bot._uptime is not None:
             return
 
-        bot._uptime = datetime.datetime.utcnow()
+        bot._uptime = datetime.utcnow()
 
         guilds = len(bot.guilds)
         users = len(set([m for m in bot.get_all_members()]))
@@ -313,7 +312,7 @@ def init_events(bot, cli_flags):
             not bot._checked_time_accuracy
             or (discord_now - timedelta(minutes=60)) > bot._checked_time_accuracy
         ):
-            system_now = datetime.datetime.utcnow()
+            system_now = datetime.utcnow()
             diff = abs((discord_now - system_now).total_seconds())
             if diff > 60:
                 log.warning(
diff --git a/redbot/core/modlog.py b/redbot/core/modlog.py
index a25a3f1e6..0cf9af524 100644
--- a/redbot/core/modlog.py
+++ b/redbot/core/modlog.py
@@ -2,7 +2,7 @@ from __future__ import annotations
 
 import asyncio
 import logging
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from typing import List, Literal, Union, Optional, cast, TYPE_CHECKING
 
 import discord
@@ -127,7 +127,8 @@ async def _init(bot: Red):
                 if entry:
                     if entry.user.id != guild.me.id:
                         # Don't create modlog entires for the bot's own bans, cogs do this.
-                        mod, reason, date = entry.user, entry.reason, entry.created_at
+                        mod, reason = entry.user, entry.reason
+                        date = entry.created_at.replace(tzinfo=timezone.utc)
                         await create_case(_bot_ref, guild, date, "ban", member, mod, reason)
                     return
 
@@ -163,7 +164,8 @@ async def _init(bot: Red):
                 if entry:
                     if entry.user.id != guild.me.id:
                         # Don't create modlog entires for the bot's own unbans, cogs do this.
-                        mod, reason, date = entry.user, entry.reason, entry.created_at
+                        mod, reason = entry.user, entry.reason
+                        date = entry.created_at.replace(tzinfo=timezone.utc)
                         await create_case(_bot_ref, guild, date, "unban", user, mod, reason)
                     return
 
@@ -351,9 +353,9 @@ class Case:
         until = None
         duration = None
         if self.until:
-            start = datetime.fromtimestamp(self.created_at)
-            end = datetime.fromtimestamp(self.until)
-            end_fmt = end.strftime("%Y-%m-%d %H:%M:%S")
+            start = datetime.utcfromtimestamp(self.created_at)
+            end = datetime.utcfromtimestamp(self.until)
+            end_fmt = end.strftime("%Y-%m-%d %H:%M:%S UTC")
             duration = end - start
             dur_fmt = _strfdelta(duration)
             until = end_fmt
@@ -374,7 +376,7 @@ class Case:
         last_modified = None
         if self.modified_at:
             last_modified = "{}".format(
-                datetime.fromtimestamp(self.modified_at).strftime("%Y-%m-%d %H:%M:%S")
+                datetime.utcfromtimestamp(self.modified_at).strftime("%Y-%m-%d %H:%M:%S UTC")
             )
 
         if isinstance(self.user, int):
@@ -413,7 +415,7 @@ class Case:
                 emb.add_field(name=_("Amended by"), value=amended_by)
             if last_modified:
                 emb.add_field(name=_("Last modified at"), value=last_modified)
-            emb.timestamp = datetime.fromtimestamp(self.created_at)
+            emb.timestamp = datetime.utcfromtimestamp(self.created_at)
             return emb
         else:
             user = filter_mass_mentions(filter_urls(user))  # Further sanitization outside embeds
diff --git a/tests/cogs/test_mod.py b/tests/cogs/test_mod.py
index a82ed27c3..0d2908a4f 100644
--- a/tests/cogs/test_mod.py
+++ b/tests/cogs/test_mod.py
@@ -12,7 +12,7 @@ async def test_modlog_register_casetype(mod):
 
 @pytest.mark.asyncio
 async def test_modlog_case_create(mod, ctx, member_factory):
-    from datetime import datetime as dt
+    from datetime import datetime, timezone
 
     # Run casetype register test to register casetype in this test too
     await test_modlog_register_casetype(mod)
@@ -23,7 +23,7 @@ async def test_modlog_case_create(mod, ctx, member_factory):
     case_type = "ban"
     moderator = ctx.author
     reason = "Test 12345"
-    created_at = dt.utcnow()
+    created_at = datetime.now(timezone.utc)
     case = await mod.create_case(bot, guild, created_at, case_type, usr, moderator, reason)
     assert case is not None
     assert case.user == usr