diff --git a/app/services/commands/alias/add.rb b/app/services/commands/alias/add.rb
new file mode 100644
index 00000000..a5145e48
--- /dev/null
+++ b/app/services/commands/alias/add.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+module Commands
+  module Alias
+    class Add < Base
+      argument shortcut: 0
+      argument command:  (1..)
+
+      # Determine if the argument matches this command.
+      #
+      # @return [Boolean]
+      def self.match?(arguments)
+        arguments.first == I18n.t("commands.lookup.alias.arguments.add")
+      end
+
+      private
+
+      # Returns the command, ensuring a forward slash is present.
+      #
+      # @return [String]
+      def command
+        value = parameters[:command]
+
+        unless value.start_with?("/")
+          value = "/#{value}"
+        end
+
+        value
+      end
+
+      # Return the handler for a successful command execution.
+      #
+      # @return [Success]
+      def success
+        Success.new(character: character, command: command, shortcut: parameters[:shortcut])
+      end
+
+      # Validate if the command is valid.
+      #
+      # @return [Boolean] If the alias exists or not.
+      def validate_command
+        parsed = Command::Parser.call(command)
+
+        if parsed == Commands::Unknown
+          InvalidCommand.new(command: command)
+        end
+      end
+    end
+  end
+end
diff --git a/app/services/commands/alias/add/invalid_command.rb b/app/services/commands/alias/add/invalid_command.rb
new file mode 100644
index 00000000..687625c2
--- /dev/null
+++ b/app/services/commands/alias/add/invalid_command.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module Commands
+  module Alias
+    class Add < Base
+      class InvalidCommand < Result
+        locals :command
+
+        # Initialize an alias add invalid command result.
+        #
+        # @return [void]
+        def initialize(command:)
+          @command = command
+        end
+      end
+    end
+  end
+end
diff --git a/app/services/commands/alias/add/success.rb b/app/services/commands/alias/add/success.rb
new file mode 100644
index 00000000..64813c38
--- /dev/null
+++ b/app/services/commands/alias/add/success.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Commands
+  module Alias
+    class Add < Base
+      class Success < Result
+        locals :account, :command, :shortcut
+
+        # Initialize an alias add success result.
+        #
+        # @return [void]
+        def initialize(character:, command:, shortcut:)
+          @character = character
+          @command   = command
+          @shortcut  = shortcut
+        end
+
+        # Add the alias to the character's account.
+        #
+        # @return [void]
+        def call
+          account.update!(aliases: account.aliases.merge(shortcut => command))
+        end
+
+        private
+
+        attr_reader :character, :command, :shortcut
+
+        delegate :account, to: :character
+      end
+    end
+  end
+end
diff --git a/app/views/commands/alias/add/_invalid_command.html.erb b/app/views/commands/alias/add/_invalid_command.html.erb
new file mode 100644
index 00000000..a07109d7
--- /dev/null
+++ b/app/views/commands/alias/add/_invalid_command.html.erb
@@ -0,0 +1,7 @@
+<%# locals: (command:) %>
+<tr data-chat-target="message">
+  <td class="message-alias-add-invalid-command"></td>
+  <td class="message-alias-add-invalid-command">
+    <%= t(".message", command: command) %>
+  </td>
+</tr>
diff --git a/app/views/commands/alias/add/_invalid_command.turbo_stream.erb b/app/views/commands/alias/add/_invalid_command.turbo_stream.erb
new file mode 100644
index 00000000..6c717a0c
--- /dev/null
+++ b/app/views/commands/alias/add/_invalid_command.turbo_stream.erb
@@ -0,0 +1,2 @@
+<%# locals: (command:) %>
+<%= turbo_stream.append("messages", partial: "commands/alias/add/invalid_command", locals: { command: command }) %>
diff --git a/app/views/commands/alias/add/_success.html.erb b/app/views/commands/alias/add/_success.html.erb
new file mode 100644
index 00000000..1ec6427b
--- /dev/null
+++ b/app/views/commands/alias/add/_success.html.erb
@@ -0,0 +1,9 @@
+<%# locals: (account:, command:, shortcut:) %>
+<tr data-chat-target="message">
+  <td class="message-alias-add"></td>
+  <td class="message-alias-add">
+    <%= t(".message", command: command, shortcut: shortcut) %></td>
+  </td>
+</tr>
+
+<script>window.Miroha.Settings.aliases = <%== account.aliases.to_json %>;</script>
diff --git a/app/views/commands/alias/add/_success.turbo_stream.erb b/app/views/commands/alias/add/_success.turbo_stream.erb
new file mode 100644
index 00000000..b930d7e4
--- /dev/null
+++ b/app/views/commands/alias/add/_success.turbo_stream.erb
@@ -0,0 +1,2 @@
+<%# locals: (account:, command:, shortcut:) %>
+<%= turbo_stream.append("messages", partial: "commands/alias/add/success", locals: { account: account, command: command, shortcut: shortcut }) %>
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 5f17b3ab..b7f40543 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -75,6 +75,11 @@ en:
 
   commands:
     alias:
+      add:
+        invalid_command:
+          message: "There is no \"%{command}\" command."
+        success:
+          message: "The alias \"%{shortcut}\" has been added for the \"%{command}\" command."
       list:
         success:
           header:
@@ -147,6 +152,7 @@ en:
       alias:
         name: "alias"
         arguments:
+          add: "add"
           list: "list"
           remove: "remove"
           show: "show"
diff --git a/spec/features/commands/alias/add_spec.rb b/spec/features/commands/alias/add_spec.rb
new file mode 100644
index 00000000..b5e2016a
--- /dev/null
+++ b/spec/features/commands/alias/add_spec.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe "Sending the alias add command", :js do
+  let(:character) { create(:character) }
+  let(:command)   { "/alias add #{shortcut} #{name}" }
+  let(:name)      { "/emote" }
+  let(:shortcut)  { "/e" }
+
+  before do
+    sign_in_as_character character
+  end
+
+  it "displays the alias add command message to the sender" do
+    send_text(command)
+
+    expect(page).to have_alias_add_command_message(command: name, shortcut: shortcut)
+  end
+
+  it "does not broadcast the message to the room" do
+    using_session(:nearby_character) do
+      sign_in_as_character create(:character, room: character.room)
+    end
+
+    send_text(command)
+
+    wait_for(have_alias_add_command_message(command: name, shortcut: shortcut)) do
+      using_session(:nearby_character) do
+        expect(page).not_to have_alias_add_command_message(command: name, shortcut: shortcut)
+      end
+    end
+  end
+
+  context "with an invalid command" do
+    let(:command) { "/alias add /f #{name}" }
+    let(:name)    { "/fake" }
+
+    it "displays invalid command message to the sender" do
+      send_text(command)
+
+      expect(page).to have_invalid_command_message(command: name)
+    end
+
+    it "does not broadcast the message to the room" do
+      using_session(:nearby_character) do
+        sign_in_as_character create(:character, room: character.room)
+      end
+
+      send_text(command)
+
+      wait_for(have_invalid_command_message(command: name)) do
+        using_session(:nearby_character) do
+          expect(page).not_to have_invalid_command_message(command: name)
+        end
+      end
+    end
+  end
+
+  protected
+
+  def have_alias_add_command_message(command:, shortcut:)
+    have_css(
+      "#messages .message-alias-add",
+      text: t("commands.alias.add.success.message", command: command, shortcut: shortcut)
+    )
+  end
+
+  def have_invalid_command_message(command:)
+    have_css(
+      "#messages .message-alias-add-invalid-command",
+      text: t("commands.alias.add.invalid_command.message", command: command)
+    )
+  end
+end
diff --git a/spec/services/commands/alias/add/invalid_command_spec.rb b/spec/services/commands/alias/add/invalid_command_spec.rb
new file mode 100644
index 00000000..3d50fa5d
--- /dev/null
+++ b/spec/services/commands/alias/add/invalid_command_spec.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe Commands::Alias::Add::InvalidCommand, type: :service do
+  describe "class" do
+    it "inherits from command result" do
+      expect(described_class.superclass).to eq(Commands::Result)
+    end
+  end
+
+  describe "#locals" do
+    subject { instance.locals }
+
+    let(:command)  { double }
+    let(:instance) { described_class.new(command: command) }
+
+    it { is_expected.to eq(command: command) }
+  end
+end
diff --git a/spec/services/commands/alias/add/success_spec.rb b/spec/services/commands/alias/add/success_spec.rb
new file mode 100644
index 00000000..9a38bd5e
--- /dev/null
+++ b/spec/services/commands/alias/add/success_spec.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe Commands::Alias::Add::Success, type: :service do
+  describe "class" do
+    it "inherits from command result" do
+      expect(described_class.superclass).to eq(Commands::Result)
+    end
+  end
+
+  describe "#call" do
+    subject(:call) { instance.call }
+
+    let(:account)   { character.account }
+    let(:character) { create(:character) }
+    let(:command)   { "/emote" }
+    let(:instance)  { described_class.new(character: character, command: command, shortcut: shortcut) }
+    let(:shortcut)  { "/e" }
+
+    it "adds the alias to the character's account" do
+      call
+
+      expect(account.aliases).to have_key(shortcut)
+    end
+  end
+
+  describe "#locals" do
+    subject { instance.locals }
+
+    let(:character) { build_stubbed(:character) }
+    let(:command)   { double }
+    let(:instance)  { described_class.new(character: character, command: command, shortcut: shortcut) }
+    let(:shortcut)  { double }
+
+    it { is_expected.to eq(account: character.account, command: command, shortcut: shortcut) }
+  end
+end
diff --git a/spec/services/commands/alias/add_spec.rb b/spec/services/commands/alias/add_spec.rb
new file mode 100644
index 00000000..1c5a8834
--- /dev/null
+++ b/spec/services/commands/alias/add_spec.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe Commands::Alias::Add, type: :service do
+  describe ".match?" do
+    subject { described_class.match?(arguments) }
+
+    context "with no arguments" do
+      let(:arguments) { [] }
+
+      it { is_expected.to be(false) }
+    end
+
+    context "with add argument" do
+      let(:arguments) { [t("commands.lookup.alias.arguments.add")] }
+
+      it { is_expected.to be(true) }
+    end
+
+    context "with other arguments" do
+      let(:arguments) { %w(fake list) }
+
+      it { is_expected.to be(false) }
+    end
+  end
+
+  describe "#call" do
+    subject(:call) { instance.call }
+
+    let(:character) { build_stubbed(:character) }
+    let(:instance)  { described_class.new("/alias add #{shortcut} #{command}", character: character) }
+
+    context "with a valid shortcut and command" do
+      let(:command)  { "/emote" }
+      let(:result)   { instance_double(described_class::Success) }
+      let(:shortcut) { "/e" }
+
+      before do
+        allow(result).to receive(:call)
+        allow(described_class::Success).to receive(:new)
+          .with(character: character, command: command, shortcut: shortcut)
+          .and_return(result)
+      end
+
+      it "delegates to success handler" do
+        call
+
+        expect(result).to have_received(:call).with(no_args)
+      end
+    end
+
+    context "with a valid shortcut and command, without slashes" do
+      let(:command)  { "emote" }
+      let(:result)   { instance_double(described_class::Success) }
+      let(:shortcut) { "e" }
+
+      before do
+        allow(result).to receive(:call)
+        allow(described_class::Success).to receive(:new)
+          .with(character: character, command: "/#{command}", shortcut: shortcut)
+          .and_return(result)
+      end
+
+      it "delegates to success handler" do
+        call
+
+        expect(result).to have_received(:call).with(no_args)
+      end
+    end
+
+    context "with an invalid command" do
+      let(:command)  { "/fake" }
+      let(:result)   { instance_double(described_class::InvalidCommand) }
+      let(:shortcut) { "/f" }
+
+      before do
+        allow(described_class::InvalidCommand).to receive(:new)
+          .with(command: command)
+          .and_return(result)
+      end
+
+      it "delegates to invalid command handler" do
+        allow(result).to receive(:call)
+
+        call
+
+        expect(result).to have_received(:call).with(no_args)
+      end
+    end
+  end
+end
diff --git a/spec/views/commands/alias/add/_invalid_command.html.erb_spec.rb b/spec/views/commands/alias/add/_invalid_command.html.erb_spec.rb
new file mode 100644
index 00000000..c9c83de3
--- /dev/null
+++ b/spec/views/commands/alias/add/_invalid_command.html.erb_spec.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe "commands/alias/add/_invalid_command.html.erb" do
+  subject(:html) do
+    render partial: "commands/alias/add/invalid_command",
+           locals:  { command: command }
+
+    rendered
+  end
+
+  let(:command) { "/unknown" }
+
+  it "renders the unknown alias message" do
+    expect(html).to have_message_row(
+      "td:nth-child(2)",
+      text: t("commands.alias.add.invalid_command.message", command: command)
+    )
+  end
+end
diff --git a/spec/views/commands/alias/add/_invalid_command.turbo_stream.erb_spec.rb b/spec/views/commands/alias/add/_invalid_command.turbo_stream.erb_spec.rb
new file mode 100644
index 00000000..5d309cda
--- /dev/null
+++ b/spec/views/commands/alias/add/_invalid_command.turbo_stream.erb_spec.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe "commands/alias/add/_invalid_command.turbo_stream.erb" do
+  subject(:html) do
+    render partial: "commands/alias/add/invalid_command",
+           formats: :turbo_stream,
+           locals:  { command: "/fake" }
+
+    rendered
+  end
+
+  before do
+    stub_template("commands/alias/add/_invalid_command.html.erb" => "INVALID_COMMAND_TEMPLATE")
+  end
+
+  it "appends to the messages element" do
+    expect(html).to have_turbo_stream_element(
+      action: "append",
+      target: "messages"
+    )
+  end
+
+  it "renders the HTML template" do
+    expect(html).to include("INVALID_COMMAND_TEMPLATE")
+  end
+end
diff --git a/spec/views/commands/alias/add/_success.html.erb_spec.rb b/spec/views/commands/alias/add/_success.html.erb_spec.rb
new file mode 100644
index 00000000..ad0e96e3
--- /dev/null
+++ b/spec/views/commands/alias/add/_success.html.erb_spec.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe "commands/alias/add/success.html.erb" do
+  subject(:html) do
+    render partial: "commands/alias/add/success", locals: {
+      account:  account,
+      command:  command,
+      shortcut: shortcut
+    }
+
+    rendered
+  end
+
+  let(:account)  { build_stubbed(:account) }
+  let(:command)  { "/emote" }
+  let(:shortcut) { "/e" }
+
+  it "renders the message" do
+    expect(html).to have_css(
+      "td:nth-child(2)",
+      text: t("commands.alias.add.success.message", command: command, shortcut: shortcut)
+    )
+  end
+
+  it "overwrites the local alias cache" do
+    expect(html).to include(
+      "<script>window.Miroha.Settings.aliases = #{account.aliases.to_json};</script>"
+    )
+  end
+end
diff --git a/spec/views/commands/alias/add/_success.turbo_stream.erb_spec.rb b/spec/views/commands/alias/add/_success.turbo_stream.erb_spec.rb
new file mode 100644
index 00000000..7cdbd13b
--- /dev/null
+++ b/spec/views/commands/alias/add/_success.turbo_stream.erb_spec.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe "commands/alias/add/_success.turbo_stream.erb" do
+  subject(:html) do
+    render partial: "commands/alias/add/success",
+           formats: :turbo_stream,
+           locals:  { account: account, command: "/emote", shortcut: "/e" }
+
+    rendered
+  end
+
+  let(:account) { build_stubbed(:account) }
+
+  before do
+    stub_template("commands/alias/add/_success.html.erb" => "SUCCESS_TEMPLATE")
+  end
+
+  it "appends to the messages element" do
+    expect(html).to have_turbo_stream_element(
+      action: "append",
+      target: "messages"
+    )
+  end
+
+  it "renders the HTML template" do
+    expect(html).to include("SUCCESS_TEMPLATE")
+  end
+end