How to Block a Sender in Outlook: A Complete Guide
Unwanted emails are more than an annoyance — they clutter your inbox, waste your time, and can sometimes pose security risks. Outlook gives you several ways to block senders, but the method that works best depends on which version of Outlook you're using and what you actually want to happen to those blocked messages.
What "Blocking" Actually Does in Outlook
When you block a sender in Outlook, you're adding their email address to your Blocked Senders list. Emails from that address are automatically moved to your Junk Email folder rather than your inbox. They aren't deleted outright — they sit in Junk, where you can review them if needed.
This is an important distinction. Blocking in Outlook is more accurately described as automatic junk filtering, not a hard wall. If you're expecting a true delete-on-arrival behavior, you'd need to set up a separate rule.
How to Block a Sender in Outlook on the Web (Outlook.com)
This applies to anyone using Outlook through a browser at outlook.com or outlook.live.com.
- Open an email from the sender you want to block
- Click the three-dot menu (More options) in the top-right corner of the email
- Select Block > Block sender
- Confirm when prompted
Outlook will immediately move existing emails from that sender to Junk and route all future messages there automatically.
How to Block a Sender in the Outlook Desktop App
The desktop version of Outlook — part of Microsoft 365 or older standalone Office packages — follows a slightly different path.
- Right-click the email from the sender you want to block
- Hover over Junk
- Select Block Sender
That's it. The address is added to your Blocked Senders list, and future emails from that address land in Junk.
You can also manage your full Blocked Senders list manually:
- Go to Home > Junk > Junk Email Options
- Click the Blocked Senders tab
- Add, edit, or remove addresses directly
How to Block a Sender in Outlook on Mobile (iOS and Android)
The Outlook mobile app has a streamlined interface, so the steps differ slightly from desktop.
- Open the email from the sender
- Tap the three-dot menu in the top-right corner
- Select Block sender or Move to Junk depending on your app version
📱 Note: The mobile app's blocking options have varied across versions and platform updates. If you don't see a direct "Block sender" option, moving the email to Junk and marking it as junk often achieves a similar result and can train the filter over time.
Using Rules for More Control
If you want more than basic junk filtering — for example, automatically deleting messages from a sender rather than sending them to Junk — Outlook's Rules feature gives you that control.
In the desktop app:
- Right-click an email from the sender
- Select Rules > Create Rule
- Set the condition to match the sender's address
- Choose the action: delete it, move it to a specific folder, or mark it as read
In Outlook on the web:
- Go to Settings > View all Outlook settings > Mail > Rules
- Click Add new rule
- Define your conditions and actions
Rules are especially useful when you want different behavior for different senders — for instance, silently archiving newsletters versus immediately deleting promotional spam.
Variables That Affect How Blocking Works
Not all blocking behaves the same way, and several factors determine what actually happens:
| Variable | How It Affects Blocking |
|---|---|
| Outlook version | Desktop app, web, and mobile have different menu paths |
| Account type | Microsoft 365, Outlook.com, Exchange, and IMAP accounts may behave differently |
| Sender spoofing | Blocked addresses won't catch spoofed emails using different addresses |
| Domain vs. address | Blocking one address doesn't block the whole domain unless you add the domain separately |
| IT/admin policies | Work or school accounts managed by an organization may restrict junk settings |
🔒 One limitation worth knowing: sophisticated spam and phishing campaigns frequently rotate sending addresses, so blocking a specific address may only stop that particular address — not the broader campaign.
Blocking a Whole Domain
If you're getting spam from multiple addresses at the same company or domain, you can block the entire domain rather than individual senders.
In Junk Email Options on desktop, add the domain in the format @example.com to your Blocked Senders list. Any email from that domain will be routed to Junk automatically.
Use this carefully — blocking a whole domain means you'll miss legitimate emails from anyone at that organization too.
The Difference Between Blocked Senders and Safe Senders
Outlook maintains two parallel lists:
- Blocked Senders — addresses and domains whose emails go straight to Junk
- Safe Senders — addresses and domains that always bypass the Junk filter
Understanding both matters because Outlook's junk filter uses them together. A sender on your Safe Senders list will never be caught by a block you've set for their domain — individual overrides can complicate filtering behavior if you're not keeping both lists organized.
Whether basic blocking covers your needs or you'd be better served by a custom rule comes down to how frequently the problem recurs, what type of account you're using, and whether you're dealing with a single persistent sender or rotating spam sources — each scenario points toward a different configuration.