How to Block an Email Address in Outlook (Step-by-Step Guide)

To block an email address in Outlook, right-click the sender's message, choose Junk > Block Sender, and confirm. The sender goes onto your Blocked Senders list, and all future mail from that address moves straight to the Junk Email folder. The exact path varies slightly between Outlook on the web, Outlook for Windows, Outlook for Mac, and the Outlook mobile app, but every version uses the same Blocked Senders list that syncs across your devices through your Microsoft 365 or Outlook.com account.

Blocking a sender is the right move when a single address keeps sending unwanted mail and you want to filter it without setting up complex rules and filters. For broader patterns (whole domains, phrases in the subject, repeating spam from rotating addresses), Outlook has separate tools that work alongside the Blocked Senders list. This guide covers each method in order of how often you will need them.

How to Block a Sender in Outlook on the Web

Outlook on the web (outlook.live.com for personal accounts, outlook.office.com for Microsoft 365) handles blocking through the same interface for both account types.

Sign in to Outlook on the web.
Find a message from the sender you want to block.
Right-click the message in the message list, or open the message and click the three-dot menu in the top toolbar.
Hover over Block and click Block sender.
A confirmation appears. Click OK.

The sender's address is added to your Blocked Senders list. The current message moves to Junk Email, and all future messages from that address skip your inbox and go straight to Junk.

To see or edit the list, click Settings (gear icon, top right) > Mail > Junk email. You can add addresses manually, remove entries, and toggle whether attachments and links from blocked senders are filtered.

How to Block a Sender in Outlook for Windows (Classic Desktop)

The desktop Outlook for Windows app (Outlook 2016/2019/2021 and the Microsoft 365 classic desktop client) uses the same Blocked Senders list as the web, but the interface is different.

Open Outlook for Windows.
Select a message from the sender in your inbox.
On the Home ribbon, click Junk.
Choose Block Sender.
Click OK in the confirmation dialog.

The sender goes onto the Blocked Senders list. Future mail from the address is automatically routed to the Junk Email folder.

To manage the list, click Home > Junk > Junk Email Options. The Blocked Senders tab lists every blocked address and lets you add, edit, or remove entries.

New Outlook for Windows

Microsoft is rolling out a new Outlook for Windows app that replaces the classic one and matches the Outlook on the web interface. If you are on the new app:

Right-click the sender's message.
Select Block > Block sender.
Confirm in the dialog.

Block actions sync immediately to your Outlook on the web account and to all your other Outlook clients signed in to the same Microsoft account.

How to Block a Sender in Outlook for Mac

Outlook for Mac handles blocking through the Junk submenu, similar to Windows.

Open Outlook for Mac.
Select the message from the sender in your inbox.
From the Message menu (or right-click the message), choose Junk Mail > Block Sender.
Confirm the action.

To manage the list, go to Outlook > Preferences > Junk > Blocked Senders. You can add, edit, or remove addresses from here.

How to Block a Sender in the Outlook Mobile App

The Outlook mobile app on iOS and Android supports blocking, though the path is slightly hidden.

Open the Outlook mobile app.
Open a message from the sender you want to block.
Tap the three-dot menu in the top right.
Tap Move to Junk (this also adds the sender to your Blocked Senders list).
Confirm.

The mobile app does not always show a dedicated "Block sender" option. Moving the message to Junk has the same effect because Outlook treats the action as a signal to add the sender to the Blocked Senders list for the account.

You cannot view or edit the Blocked Senders list directly in the mobile app. To manage it, sign in to Outlook on the web and use the Junk email settings there.

How to Block an Entire Domain in Outlook

If unwanted mail keeps coming from different addresses on the same domain (for example, multiple senders from spam-marketing-domain.com), block the whole domain instead of individual addresses.

In Outlook on the Web

Click Settings (gear icon) > Mail > Junk email.
Under Blocked senders and domains, click Add.
Enter the domain in the format @example.com (the leading @ is what tells Outlook to match every address on that domain).
Press Enter, then click Save.

In Outlook for Windows (Classic)

Click Home > Junk > Junk Email Options.
Open the Blocked Senders tab.
Click Add.
Type the domain in the form @example.com.
Click OK twice.

Domain blocks catch every address on that domain, including new ones the sender creates later. This is the right tool for marketing lists and spam farms that rotate their from-addresses to evade individual blocks.

How to Unblock a Sender in Outlook

Unblocking reverses the action. The sender's mail returns to your inbox starting with the next message they send.

In Outlook on the Web

Click Settings > Mail > Junk email.
Under Blocked senders and domains, find the entry you want to remove.
Click the trash can icon next to the address.
Click Save.

In Outlook for Windows or Mac

Open Junk Email Options (Windows) or Preferences > Junk (Mac).
Open the Blocked Senders tab.
Select the address.
Click Remove.
Click OK.

The Blocked Senders list syncs across every Outlook client signed in to the same Microsoft account, so an unblock done in any one place applies everywhere.

Block Sender vs Junk Mail vs Rules: When to Use Which

Outlook has three overlapping tools for filtering unwanted mail. Each is best for different situations.

Tool	What it does	When to use
Block Sender	Adds the address to Blocked Senders; future mail goes straight to Junk Email	A specific address sends repeated unwanted mail
Junk Mail (Junk)	Marks current message as junk and feeds Outlook's spam-learning system	Random spam with no clear sender pattern
Rules	Custom logic on any field (sender, subject, content); can delete or move mail	Complex patterns or organising legitimate mail differently

For most cases, Block Sender is the right starting point. If unwanted mail keeps slipping through under different addresses, move to Junk Mail and let Outlook's spam learning improve. If you need fine-grained control (block mail with specific subject phrases, or move mail from a sender to a folder other than Junk), set up a custom rule.

Best Practices for Blocking in Outlook

Block addresses, not whole domains, for legitimate companies. Blocking @amazon.com to stop marketing mail will also block order confirmations and shipping updates. Unsubscribe instead.
Review the Blocked Senders list quarterly. Old entries clutter the list and can hide active blocks you actually need. Remove anything you do not recognize.
Use domain blocks for spam farms. When a sender clearly rotates their from-address (different name, same domain), one domain block beats blocking ten individual addresses.
Combine with rules for advanced cases. Block Sender only filters by address. To block based on subject keywords, content, or sender display name patterns, create a rule that moves mail to Junk or deletes it directly.
Check Junk Email regularly. Outlook's blocked-sender filter can occasionally catch legitimate mail. A weekly scan of the Junk Email folder catches false positives before they expire (Junk Email auto-deletes after 30 days by default).

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Frequently Asked Questions

Does blocking a sender in Outlook stop them from emailing me?

No. Blocking only changes where their messages go on your end. The sender does not receive any notice and can keep emailing you. Their mail just lands in your Junk Email folder instead of your inbox, and after 30 days Outlook deletes it automatically.

Will the blocked sender know they were blocked?

No. Outlook does not notify a sender when they are blocked. Their mail still appears delivered from their side. They will not see a bounce message or any other signal.

What is the difference between Block and Unsubscribe in Outlook?

Blocking adds the sender to your local Blocked Senders list and filters future mail to Junk. Unsubscribing sends a request to the sender's mailing list to remove your address. For legitimate marketing mail, unsubscribe first - it stops the mail at the source. For persistent unwanted mail or mail from senders who ignore unsubscribe requests, block them.

How many senders can I block in Outlook?

The Blocked Senders list supports up to 1,024 entries per account in Outlook for Microsoft 365 and Outlook.com. If you hit the limit, remove old entries before adding new ones, or move to domain blocks to consolidate multiple addresses under a single rule.

Why are blocked senders still appearing in my inbox?

A few common causes: the block was set up on a different Outlook account (check you are signed in to the right one), the sender is using a different address on the same domain (use a domain block instead), the block is still syncing across devices (give it a few minutes), or the message is forwarded from another address (the original sender field does not match the Blocked Senders list). Check the message headers to see the actual sending address.