Block a sender in Outlook on the web

Open the email from the sender you want to block. Click the three dots (more actions) at the top right of the message. Select Block from the menu. Outlook moves all future emails from that address to your Junk folder automatically.

If you want to block someone without opening their email, right-click the message in your inbox and choose Block from the context menu. The block takes effect when ready — you will not see new messages from that sender in your inbox, though they will still arrive in Junk where you can review them if needed.

To unblock a sender later, go to Settings (the gear icon), then Mail, then Junk email. Find the blocked sender in the Blocked senders and domains list and click the X next to their name.

Block a sender in Outlook desktop app

Right-click the email from the person you want to block. Select Junk, then Block Sender. Outlook adds that address to your blocked list and sends future messages to Junk.

You can also open the email and use the ribbon at the top. Click Junk (in the Delete group), then Block Sender. The result is the same — the sender goes on your blocked list.

To see all blocked senders, go to File, then Options, then Trust Center, then Trust Center Settings, then Junk Email. The Blocked Senders tab shows everyone you have blocked. Click a name and select Remove to unblock them.

Key Takeaways

  • In Outlook on the web, click the three dots on any email and select Block to send that sender's future messages to Junk.
  • In the Outlook desktop app, right-click an email, choose Junk, then Block Sender to add that address to your blocked list.
  • Blocked senders' emails still arrive in your Junk folder — they are not deleted, just hidden from your inbox.
  • You can unblock a sender at any time through Settings (web) or File > Options > Trust Center (desktop).
  • Blocking works on individual email addresses, so if someone sends from a different address, you will need to block that one separately.

Block an entire domain in Outlook

If you want to block all emails from a company or organization, you can block the entire domain instead of one address. In Outlook on the web, go to Settings, then Mail, then Junk email. Under Blocked senders and domains, type the domain name (for example, example.com) and click Add.

In the Outlook desktop app, go to File > Options > Trust Center > Trust Center Settings > Junk Email. Click the Blocked Senders tab, then Add. Type the domain name and click OK. Every email from anyone at that domain will go to Junk.

What happens when you block someone

Blocking a sender does not delete their old emails — they stay in your inbox unless you delete them yourself. Only new messages from that address go to Junk. The sender does not receive a notification that you blocked them, and they can still send you emails (you just will not see them in your inbox).

If you block someone by mistake, unblocking is when ready. Go back to your blocked senders list, find the address, and remove it. The next email from that person will arrive in your inbox normally.

Block someone who is spoofing another address

Sometimes spam comes from an address that looks like it belongs to someone you know — this is called spoofing. Blocking the fake address will not stop the real person's emails, because the spammer is using a forged sender address. Instead, report the email as phishing: in Outlook on the web, click the three dots and select Report phishing. In the desktop app, click Junk, then Phishing.

Reporting phishing helps Outlook's spam filters learn to catch similar emails in the future. If you know the real sender's actual address, you can add them to your contacts or safe senders list so their real emails always reach your inbox.

Frequently Asked Questions

Can I block emails from a phone number or text message?

Outlook's block feature works only on email addresses. If you are receiving unwanted text messages, use your phone's built-in blocking tools instead. Most phones have a block or spam feature in the Messages or Phone app.

Will the blocked person know I blocked them?

No. Outlook does not notify senders when you block them. They can still send emails — the messages just go to your Junk folder instead of your inbox. They have no way to know whether you blocked them or straightforward did not reply.

What if I block someone and then they email me from a different address?

Blocking works on individual email addresses only. If someone sends from a new address, you will see that email in your inbox. You can block the new address the same way you blocked the first one. If this becomes a pattern, consider reporting the emails as phishing instead.

Can I block emails by subject line or content?

Outlook's block feature does not filter by subject or content — only by sender address or domain. If you want to filter emails by keywords, use Outlook's rules feature instead. Go to Settings > Mail > Rules (web) or File > Options > Mail > Rules and Alerts (desktop) to create a custom rule.

Do blocked emails take up storage space?

Yes. Blocked emails sit in your Junk folder and count toward your mailbox storage limit. If you want to free up space, you can permanently delete them. Go to Junk, select the emails from the blocked sender, and delete them.