diff --git a/Commands/Bot/eval.js b/Commands/Bot/eval.js
index ea95349..4363e39 100644
--- a/Commands/Bot/eval.js
+++ b/Commands/Bot/eval.js
@@ -1,11 +1,11 @@
-const Command = require("../../Structure/Command.js");
+const Command = require(`../../Structure/Command.js`);
 
 module.exports = class extends Command {
     constructor(client) {
         super(client, {
-            name: "eval",
-            description: "Eval a js code.",
-            category: "Bot",
+            name: `eval`,
+            description: `Eval a js code.`,
+            category: `Bot`,
             enabled: true,
             aliases: [],
             cooldown: 3,
@@ -14,12 +14,12 @@ module.exports = class extends Command {
     }
 
     async run(message, args, data) {
-        if (parseInt(message.author.id) !== parseInt(data.config.ownerID)) return message.chat.sendMessage("You do not have the permission to use this command")
+        if (parseInt(message.author.id) !== parseInt(data.config.ownerID)) return message.chat.sendMessage(`You do not have the permission to use this command.`)
         let result = new Promise((resolve) => resolve(eval(args.join(` `))));
 
         return result.then((output) => {
-            if (typeof output !== "string") {
-                output = require("util").inspect(output, { depth: 0 });
+            if (typeof output !== `string`) {
+                output = require(`util`).inspect(output, { depth: 0 });
             }
             message.chat.sendMessage(output)
         }).catch((err) => {
diff --git a/Commands/Bot/ping.js b/Commands/Bot/ping.js
index fd61fc1..627d2c9 100644
--- a/Commands/Bot/ping.js
+++ b/Commands/Bot/ping.js
@@ -1,20 +1,20 @@
-const Command = require("../../Structure/Command.js");
+const Command = require(`../../Structure/Command.js`);
 
 module.exports = class extends Command {
     constructor(client) {
         super(client, {
-            name: "ping",
-            description: "Return the bot ping.",
-            category: "Bot",
+            name: `ping`,
+            description: `Return the bot ping.`,
+            category: `Bot`,
             enabled: true,
-            aliases: ["latency"],
+            aliases: [`latency`],
             cooldown: 3,
             dmOnly: false,
         });
     }
 
     async run(message, args) {
-        message.chat.sendMessage('Fetching ping...').then(m => {
+        message.chat.sendMessage(`Fetching ping...`).then(m => {
             m.delete();
             message.chat.sendMessage(`My ping is currently at ${(m.timestamp - message.timestamp) / 1000}ms\nI use ${(process.memoryUsage().heapUsed / 1024 / 1024).toFixed(2)}mb of RAM`)
         })
diff --git a/Commands/Bot/prefix.js b/Commands/Bot/prefix.js
new file mode 100644
index 0000000..4f9f53d
--- /dev/null
+++ b/Commands/Bot/prefix.js
@@ -0,0 +1,36 @@
+const Command = require(`../../Structure/Command.js`);
+
+module.exports = class extends Command {
+    constructor(client) {
+        super(client, {
+            name: `prefix`,
+            description: `Configure the bot prefix.`,
+            category: `Bot`,
+            enabled: true,
+            aliases: [],
+            cooldown: 3,
+            dmOnly: false,
+        });
+    }
+
+    async run(message, args, data) {
+        if (message.chat.isGroup && !message.chat.adminUserIDs.includes(parseInt(message.author.id))) return message.chat.sendMessage(`You do not have the permission to use this command.`);
+        let prefix = args[0];
+		if(!prefix){
+			return message.chat.sendMessage(`Please specify an argument.`);
+		}
+		if(prefix.length > 5){
+			return message.chat.sendMessage(`The prefix cannot be longer than 5 characters.`);
+		}
+        
+        if (message.chat.isGroup) {
+            data.groups.prefix = prefix;
+            data.groups.save();
+        } else {
+            data.users.prefix = prefix;
+            data.users.save();
+        }
+
+		message.chat.sendMessage(`The prefix is now: ${prefix}`);
+    }
+}
\ No newline at end of file
diff --git a/Events/messageCreate.js b/Events/messageCreate.js
index aa1189e..50627ff 100644
--- a/Events/messageCreate.js
+++ b/Events/messageCreate.js
@@ -11,17 +11,20 @@ module.exports = class {
 
         if (message.authorID === this.client.user.id) return;
         message.markSeen();
+        let prefix;
         if (message.chat.isGroup) {
             const groupMembersData = await this.client.findOrCreateGroupMember({ id: message.author.id, groupID: message.chat.id });
             data.groupMembers = groupMembersData;
             const groupsData = await this.client.findOrCreateGroup({ groupID: message.chat.id });
             data.groups = groupsData;
+            prefix = data.groups.prefix;
         } else {
             const usersData = await this.client.findOrCreateUser({ id: message.author.id });
             data.users = usersData;
+            prefix = data.users.prefix;
         }
 
-        let prefixes = this.client.config.defaultPrefix;
+        let prefixes = prefix || this.client.config.defaultPrefix;
         if (message.content.indexOf(prefixes) !== 0) return;
         let args = message.content.slice(prefixes.length).trim().split(/ +/g);
         let command = args.shift().toLowerCase();
diff --git a/Models/Groups.js b/Models/Groups.js
index e3e0517..bdeef5e 100644
--- a/Models/Groups.js
+++ b/Models/Groups.js
@@ -1,5 +1,6 @@
 const mongoose = require(`mongoose`),
-    Schema = mongoose.Schema;
+    Schema = mongoose.Schema,
+    config = require(`../config`);
 
 module.exports = mongoose.model(`Groups`, new Schema({
     groupID: String,
@@ -7,4 +8,8 @@ module.exports = mongoose.model(`Groups`, new Schema({
         type: Array,
         default: []
     },
+    prefix: {
+        type: String,
+        default: config.defaultPrefix,
+    }
 }));
diff --git a/Models/Users.js b/Models/Users.js
index d554f58..1e05d9c 100644
--- a/Models/Users.js
+++ b/Models/Users.js
@@ -1,5 +1,6 @@
 const mongoose = require(`mongoose`),
-    Schema = mongoose.Schema;
+    Schema = mongoose.Schema,
+    config = require(`../config`);
 
 module.exports = mongoose.model(`Users`, new Schema({
     id: String,
@@ -7,4 +8,8 @@ module.exports = mongoose.model(`Users`, new Schema({
         type: Array,
         default: []
     },
+    prefix: {
+        type: String,
+        default: config.defaultPrefix,
+    }
 }));
diff --git a/README.md b/README.md
index 6b0e005..86f190a 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,7 @@ it means that the bot is ready to be used. 🎉
 - !ping: Return the bot ping.
 - !help: Return the bot commands list.
 - !eval: Eval a JS code.
+- !prefix: Change the bot's prefix for groups or private chats.
 
 
 ## Images