diff --git a/toot/cli/__init__.py b/toot/cli/__init__.py
index f36d70a..0c71cb3 100644
--- a/toot/cli/__init__.py
+++ b/toot/cli/__init__.py
@@ -4,11 +4,14 @@ import os
 import sys
 import typing as t
 
+from click.shell_completion import CompletionItem
 from click.testing import Result
+from click.types import StringParamType
 from functools import wraps
+
 from toot import App, User, config, __version__
-from toot.settings import get_settings
 from toot.output import print_warning
+from toot.settings import get_settings
 
 if t.TYPE_CHECKING:
     import typing_extensions as te
@@ -89,10 +92,24 @@ class TootObj(t.NamedTuple):
     """Data to add to Click context"""
     color: bool = True
     debug: bool = False
+    as_user: t.Optional[str] = None
     # Pass a context for testing purposes
     test_ctx: t.Optional[Context] = None
 
 
+class AccountParamType(StringParamType):
+    """Custom type to add shell completion for account names"""
+    name = "account"
+
+    def shell_complete(self, ctx, param, incomplete: str):
+        users = config.load_config()["users"].keys()
+        return [
+            CompletionItem(u)
+            for u in users
+            if u.lower().startswith(incomplete.lower())
+        ]
+
+
 def pass_context(f: "t.Callable[te.Concatenate[Context, P], R]") -> "t.Callable[P, R]":
     """Pass the toot Context as first argument."""
     @wraps(f)
@@ -110,9 +127,14 @@ def get_context() -> Context:
     if obj.test_ctx:
         return obj.test_ctx
 
-    user, app = config.get_active_user_app()
-    if not user or not app:
-        raise click.ClickException("This command requires you to be logged in.")
+    if obj.as_user:
+        user, app = config.get_user_app(obj.as_user)
+        if not user or not app:
+            raise click.ClickException(f"Account '{obj.as_user}' not found. Run `toot auth` to see available accounts.")
+    else:
+        user, app = config.get_active_user_app()
+        if not user or not app:
+            raise click.ClickException("This command requires you to be logged in.")
 
     return Context(app, user, obj.color, obj.debug)
 
@@ -129,11 +151,12 @@ json_option = click.option(
 @click.option("-w", "--max-width", type=int, default=80, help="Maximum width for content rendered by toot")
 @click.option("--debug/--no-debug", default=False, help="Log debug info to stderr")
 @click.option("--color/--no-color", default=sys.stdout.isatty(), help="Use ANSI color in output")
+@click.option("--as", "as_user", type=AccountParamType(), help="The account to use, overrides the active account.")
 @click.version_option(__version__, message="%(prog)s v%(version)s")
 @click.pass_context
-def cli(ctx: click.Context, max_width: int, color: bool, debug: bool):
+def cli(ctx: click.Context, max_width: int, color: bool, debug: bool, as_user: str):
     """Toot is a Mastodon CLI"""
-    ctx.obj = TootObj(color, debug)
+    ctx.obj = TootObj(color, debug, as_user)
     ctx.color = color
     ctx.max_content_width = max_width
 
diff --git a/toot/cli/auth.py b/toot/cli/auth.py
index c72f0c4..b7d32e6 100644
--- a/toot/cli/auth.py
+++ b/toot/cli/auth.py
@@ -2,13 +2,10 @@ import click
 import platform
 import sys
 import webbrowser
-from click.shell_completion import CompletionItem
-
-from click.types import StringParamType
 
 from toot import api, config, __version__
 from toot.auth import get_or_create_app, login_auth_code, login_username_password
-from toot.cli import cli
+from toot.cli import AccountParamType, cli
 from toot.cli.validators import validate_instance
 
 
@@ -22,18 +19,6 @@ instance_option = click.option(
 )
 
 
-class AccountParamType(StringParamType):
-    """Custom type to add shell completion for account names"""
-
-    def shell_complete(self, ctx, param, incomplete: str):
-        accounts = config.load_config()["users"].keys()
-        return [
-            CompletionItem(a)
-            for a in accounts
-            if a.lower().startswith(incomplete.lower())
-        ]
-
-
 @cli.command()
 def auth():
     """Show logged in accounts and instances"""