diff --git a/README.md b/README.md
index cea0b84..4f2c2d2 100644
--- a/README.md
+++ b/README.md
@@ -37,6 +37,8 @@ latex - A simple cog originally by Stevy for v2 that displayes LaTeX expressions
 
 luigipoker - Play the Luigi Poker minigame from New Super Mario Brothers. Ported from the v2 version written by themario30.
 
+massunban - Bot Admins or guild Administrators can use this tool to mass unban users via ban reason keywords, or mass unban everyone on the ban list.
+
 noflippedtables - A v3 port of irdumb's v2 cog with a little extra surprise included. Unflip all the tables.
 
 nolinks - A very blunt hammer to remove anything that looks like a link. Roles can be whitelisted and it can watch multiple channels.
diff --git a/massunban/__init__.py b/massunban/__init__.py
new file mode 100644
index 0000000..e7d2027
--- /dev/null
+++ b/massunban/__init__.py
@@ -0,0 +1,7 @@
+from .massunban import MassUnban
+
+__red_end_user_data_statement__ = "This cog does not persistently store data or metadata about users."
+
+
+def setup(bot):
+    bot.add_cog(MassUnban(bot))
diff --git a/massunban/info.json b/massunban/info.json
new file mode 100644
index 0000000..7ecb9e1
--- /dev/null
+++ b/massunban/info.json
@@ -0,0 +1,7 @@
+{
+    "author": ["aikaterna"],
+    "install_msg": "Thanks for installing. Please read the help for the `massunban` command to get started, once you have loaded the cog.",
+    "short": "Mass unban users.",
+    "description": "Mass unban users by the ban reason used.",
+    "tags": ["unban"]
+}
diff --git a/massunban/massunban.py b/massunban/massunban.py
new file mode 100644
index 0000000..226abb7
--- /dev/null
+++ b/massunban/massunban.py
@@ -0,0 +1,74 @@
+import asyncio
+import discord
+from redbot.core import checks, commands
+from redbot.core.utils.predicates import MessagePredicate
+
+
+class MassUnban(commands.Cog):
+    """Unban all users, or users with a specific ban reason."""
+
+    async def red_delete_data_for_user(self, **kwargs):
+        """Nothing to delete."""
+        return
+
+    def __init__(self, bot):
+        self.bot = bot
+
+    @commands.guild_only()
+    @commands.command()
+    @checks.admin_or_permissions(manage_guild=True)
+    async def massunban(self, ctx, *, ban_reason = None):
+        """
+        Mass unban everyone, or specific people.
+        
+        `ban_reason` is what the bot looks for in the original ban reason to qualify a user for an unban. It is case-insensitive.
+        
+        When Red is used to ban a user, the ban reason looks like:
+        `action requested by aikaterna#1393 (id 154497072148643840). reason: bad person`
+        Using `[p]massunban bad person` will unban this user as "bad person" is contained in the original ban reason.
+        Using `[p]massunban aikaterna` will unban every user banned by aikaterna, if Red was used to ban them in the first place.
+        For users banned using the right-click ban option in Discord, the ban reason is only what the mod puts when it asks for a reason, so using the mod name to unban won't work.
+        
+        Every unban will show up in your modlog if mod logging is on for unbans. Check `[p]modlogset cases` to verify if mod log creation on unbans is on.
+        This can mean that your bot will be ratelimited on sending messages if you unban lots of users as it will create a modlog entry for each unban.
+        """
+        try:
+            banlist = await ctx.guild.bans()
+        except discord.errors.Forbidden:
+            msg = "I need the `Ban Members` permission to fetch the ban list for the guild."
+            await ctx.send(msg)
+            return
+
+        bancount = len(banlist)
+        if bancount == 0:
+            await ctx.send("No users are banned from this server.")
+            return
+
+        unban_count = 0
+        if not ban_reason:
+            warning_string = (
+                "Are you sure you want to unban every banned person on this server?\n"
+                f"**Please read** `{ctx.prefix}help massunban` **as this action can cause a LOT of modlog messages!**\n"
+                "Type `Yes` to confirm, or `No` to cancel."
+            )
+            await ctx.send(warning_string)
+            pred = MessagePredicate.yes_or_no(ctx)
+            try:
+                await self.bot.wait_for("message", check=pred, timeout=15)
+                if pred.result is True:
+                    for ban_entry in banlist:
+                        await ctx.guild.unban(ban_entry.user, reason=f"Mass Unban requested by {str(ctx.author)} ({ctx.author.id})")
+                        await asyncio.sleep(0.5)
+                        unban_count += 1
+                else:
+                    return await ctx.send("Alright, I'm not unbanning everyone.")
+            except asyncio.TimeoutError:
+                return await ctx.send("Response timed out. Please run this command again if you wish to try again.")
+        else:
+            for ban_entry in banlist:
+                if ban_reason.lower() in ban_entry.reason.lower():
+                    await ctx.guild.unban(ban_entry.user, reason=f"Mass Unban requested by {str(ctx.author)} ({ctx.author.id})")
+                    await asyncio.sleep(0.5)
+                    unban_count += 1
+
+        await ctx.send(f"Done. Unbanned {unban_count} users.")