Block a sender in Outlook on the web
Open the email from the sender you want to block. Click the three dots (more actions) in the top right of the message. Select Block from the menu. Outlook moves all future emails from that address to your Junk folder automatically.
You can also block a sender without opening their email. Right-click the message in your inbox, then select Block from the context menu. The result is the same — that sender's messages go straight to Junk.
To see who you have blocked, go to Settings (the gear icon), then Mail, then Junk email. Under Safe Senders and Domains, you will see a tab for Blocked Senders. You can remove someone from this list at any time by clicking the X next to their address.
Block a sender in Outlook desktop app
Right-click the email from the sender you want to block. Select Junk, then Block Sender. Outlook adds that address to your blocked list and sends future emails to the Junk folder.
If you prefer not to open the email, you can right-click it in your inbox list and choose the same option. The sender is blocked when ready.
To view or change your blocked senders list, go to Home tab, then Junk, then Junk Email Options. Click the Blocked Senders tab. You can remove addresses from this list by selecting them and clicking Remove.
Key Takeaways
- In Outlook on the web, click the three dots on an 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 achieve the same result.
- Blocked senders' emails still arrive on Outlook's servers but go directly to your Junk folder instead of your inbox.
- You can unblock a sender at any time by finding their address in your Blocked Senders list and removing them.
- Blocking a sender does not delete their past emails — those remain in your mailbox unless you delete them manually.
What happens when you block someone
When you block a sender in Outlook, their emails do not disappear from the internet or stop being sent. Instead, Outlook applies a filter that routes their messages to your Junk folder. You can still see those emails if you check Junk, but they no longer clutter your inbox.
The sender does not receive a notification that you have blocked them. They will not know their emails are going to Junk unless they contact you through another channel and you tell them. From their perspective, they are sending emails normally.
If the sender changes their email address, the block does not carry over. You would need to block the new address separately. This is why blocking works best for one-off unwanted senders rather than determined harassers who can easily create new accounts.
Blocking vs. unsubscribing
Many unwanted emails come from mailing lists or marketing senders. Before you block, look for an Unsubscribe link at the bottom of the email. Clicking it removes you from that sender's list entirely, which is cleaner than blocking because the sender stops sending to you altogether.
Blocking is better for personal emails from people you do not want to hear from, or for emails that do not include an unsubscribe option. If you unsubscribe from a legitimate mailing list and the sender keeps emailing you anyway, then blocking becomes the right next step.
Some senders hide their unsubscribe link or make it hard to find. In those cases, blocking is faster and more reliable than hunting for the option.
Blocking domains instead of individual addresses
If you are getting spam from many addresses at the same domain (for example, spammer@badsite.com, noreply@badsite.com, sales@badsite.com), you can block the entire domain instead of each address separately. In Outlook on the web, go to Settings > Mail > Junk email > Blocked Senders. Type the domain name (badsite.com) into the field and click Add.
In the desktop app, open Junk Email Options and go to the Blocked Senders tab. Type the domain name and click Add. All emails from any address at that domain will now go to Junk.
Be careful when blocking a domain — if you block a large company's domain, you might miss legitimate emails from that company. Block only domains you are certain you never want to hear from.
Recovering emails from blocked senders
If you blocked someone and later realize you need to read their emails, go to your Junk folder and look for their messages there. They will still be in Junk even after you unblock them, so you can read them without changing your block status.
To unblock the sender, open your Blocked Senders list (in Settings on the web, or in Junk Email Options on the desktop app) and click the X or Remove button next to their address. Future emails from them will now go to your inbox instead of Junk.
If you deleted emails from a blocked sender before unblocking them, those emails are gone. Outlook does not keep a separate archive of blocked messages, so deletion is permanent.
When blocking is not enough
Blocking works for unwanted emails from known senders, but it does not stop spam from random addresses or from accounts created specifically to get around your blocks. If you are receiving many emails from different addresses that look like spam, Outlook's built-in spam filter may already be catching most of them.
Check your Junk folder regularly to see what Outlook is filtering. If legitimate emails are landing there, you can mark them as Not Junk to train Outlook's filter. If spam is reaching your inbox, you can report it to Microsoft by clicking the Report button on the email.
For persistent harassment from someone using multiple accounts, consider reporting the behavior to your email provider or, if it involves threats, to law enforcement. Blocking alone cannot stop someone determined to contact you through new addresses.
Frequently Asked Questions
Can I block emails by subject line or keyword?
Outlook does not have a built-in feature to block emails by subject line or keyword. You can only block by sender address or domain. If you want to filter emails with certain words, you can create a rule in the desktop app that automatically moves them to a folder, but this is more complex than blocking.
Will blocking someone prevent them from seeing my read receipts?
No. Blocking only affects incoming emails — it does not change what information you send back to the sender. If you have read receipts turned on, the sender will still see when you open their emails if they are looking at their sent folder. Turn off read receipts in your settings if you want to hide that information.
What is the difference between blocking and marking as spam?
Blocking sends a sender's emails to your Junk folder. Marking as spam does the same thing and also reports the email to Microsoft to help improve their spam filter. Both have the same effect on your inbox — future emails go to Junk — but marking as spam helps protect other Outlook users.
Can I block emails on my phone?
Yes. In the Outlook mobile app, swipe left on an email (on iPhone) or long-press it (on Android), then select Block. The sender is added to your blocked list across all your devices, so the block applies whether you are using your phone, desktop, or web browser.
If I block someone, can they tell I have read their old emails?
No. Blocking only affects new emails going forward. It does not change whether the sender can see read receipts from emails you already opened before blocking them. If you want to hide your read status from someone, turn off read receipts in your Outlook settings.