diff --git a/riposte/__init__.py b/riposte/__init__.py
index 04008d5..b0b52b1 100644
--- a/riposte/__init__.py
+++ b/riposte/__init__.py
@@ -1 +1,2 @@
+from .group import Group  # noqa
 from .riposte import Riposte  # noqa
diff --git a/riposte/riposte.py b/riposte/riposte.py
index 3fe9d38..617115e 100644
--- a/riposte/riposte.py
+++ b/riposte/riposte.py
@@ -3,11 +3,11 @@
 from pathlib import Path
 import readline
 import shlex
-from typing import Callable, Dict, Iterable, List, Optional, Sequence
+from typing import List, Optional, Sequence
 
 from . import input_streams
-from .command import Command
 from .exceptions import CommandError, RiposteException, StopRiposteException
+from .group import Group
 from .printer.mixins import PrinterMixin
 from .printer.thread import PrinterThread
 
@@ -16,7 +16,7 @@ def is_libedit():
     return "libedit" in readline.__doc__
 
 
-class Riposte(PrinterMixin):
+class Riposte(Group, PrinterMixin):
     def __init__(
         self,
         prompt: str = "riposte:~ $ ",
@@ -24,6 +24,8 @@ def __init__(
         history_file: Path = Path.home() / ".riposte",
         history_length: int = 100,
     ):
+        super().__init__()
+
         self.banner = banner
         self.print_banner = True
         self.parser = None
@@ -31,7 +33,6 @@ def __init__(
         self.input_stream = input_streams.prompt_input(lambda: self.prompt)
 
         self._prompt = prompt
-        self._commands: Dict[str, Command] = {}
 
         self.setup_cli()
 
@@ -145,13 +146,6 @@ def _parse_line(line: str) -> List[str]:
         except ValueError as err:
             raise RiposteException(err)
 
-    def _get_command(self, command_name: str) -> Command:
-        """Resolve command name into registered `Command` object."""
-        try:
-            return self._commands[command_name]
-        except KeyError:
-            raise CommandError(f"Unknown command: {command_name}")
-
     def setup_cli(self):
         """Initialize CLI
 
@@ -180,6 +174,15 @@ def parse_cli_arguments(self) -> None:
                 Path(self.arguments.file)
             )
 
+    def register_group(self, group: Group) -> None:
+        for command in group._commands.values():
+            if command.name in self._commands:
+                raise RiposteException(
+                    f"'{command.name}' command already exists."
+                )
+
+            self._commands[command.name] = command
+
     @property
     def prompt(self):
         """Entrypoint for customizing prompt
@@ -189,33 +192,6 @@ def prompt(self):
         """
         return self._prompt
 
-    def command(
-        self,
-        name: str,
-        description: str = "",
-        guides: Dict[str, Iterable[Callable]] = None,
-    ) -> Callable:
-        """Decorator for bounding command with handling function."""
-
-        def wrapper(func: Callable):
-            if name not in self._commands:
-                self._commands[name] = Command(name, func, description, guides)
-            else:
-                raise RiposteException(f"'{name}' command already exists.")
-            return func
-
-        return wrapper
-
-    def complete(self, command: str) -> Callable:
-        """Decorator for bounding complete function with `Command`."""
-
-        def wrapper(func: Callable):
-            cmd = self._get_command(command)
-            cmd.attach_completer(func)
-            return func
-
-        return wrapper
-
     def _process(self) -> None:
         """Process input provided by the input stream.
 
diff --git a/tests/conftest.py b/tests/conftest.py
index a93b916..3dedde3 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -2,7 +2,7 @@
 
 import pytest
 
-from riposte import Riposte
+from riposte import Group, Riposte
 from riposte.command import Command
 
 
@@ -31,3 +31,8 @@ def command():
         func=Mock(name="mocked_handling_function", __annotations__={}),
         description="foo description",
     )
+
+
+@pytest.fixture
+def group():
+    return Group()
diff --git a/tests/test_riposte.py b/tests/test_riposte.py
index 818ffdb..e27a911 100644
--- a/tests/test_riposte.py
+++ b/tests/test_riposte.py
@@ -3,7 +3,7 @@
 
 import pytest
 
-from riposte import Riposte, input_streams
+from riposte import Group, Riposte, input_streams
 from riposte.command import Command
 from riposte.exceptions import CommandError, RiposteException
 
@@ -222,3 +222,36 @@ def test_parse_cli_arguments_file(mocked_input_streams, repl: Riposte):
         Path(arguments.file)
     )
     assert repl.input_stream is mocked_input_streams.file_input.return_value
+
+
+def test_register_group(repl: Riposte, group: Group):
+    @group.command("foo")
+    def foo():
+        pass
+
+    @repl.command("bar")
+    def bar():
+        pass
+
+    commands_before_register = repl._commands
+
+    repl.register_group(group)
+
+    assert repl._commands == {"foo": foo, **commands_before_register}
+
+
+def test_register_group_existing_command(repl: Riposte, group: Group):
+    @group.command("foo")
+    def foo():
+        pass
+
+    @repl.command("foo")
+    def bar():
+        pass
+
+    commands_before_register = repl._commands
+
+    with pytest.raises(RiposteException):
+        repl.register_group(group)
+
+    assert repl._commands == commands_before_register