Block a sender in Outlook on the web, desktop, or mobile
To block an email address in Outlook, open any message from that sender, select the three dots or menu icon, and choose "Block" or "Junk" depending on your version. On desktop Outlook, you can also right-click the sender's name and select "Block Sender". Once blocked, messages from that address go straight to your Junk folder and you will not see notifications for them.
The steps differ slightly between Outlook on the web (the browser version), Outlook desktop (the installed program), and Outlook mobile apps, but the result is the same: the sender lands in Junk and stays there unless you unblock them later.
Key Takeaways
- Blocking a sender in Outlook sends their future messages to Junk automatically, but does not delete messages already in your inbox.
- On desktop Outlook, right-click any message from the sender and select "Block Sender" from the menu.
- On Outlook on the web, open a message from the sender, click the three dots, and select "Block".
- Blocked senders can be unblocked at any time through Outlook settings or by right-clicking their name in your Junk folder.
- Blocking is different from marking as spam — blocked mail goes to Junk, but Outlook does not learn from the block the way it learns from spam reports.
Block a sender in Outlook desktop
Open any email message from the sender you want to block. Right-click on the sender's name or email address at the top of the message. A menu will appear with several options.
Select "Block Sender" from the menu. Outlook will confirm that the sender has been blocked. From that moment forward, all messages from that address will bypass your inbox and go directly to the Junk folder. You will not receive notifications when they arrive.
If you do not see "Block Sender" in the right-click menu, try clicking the message itself first to make sure it is selected, then right-click the sender's name again. In some versions of Outlook, the option may also appear under a "Junk" submenu.
Block a sender in Outlook on the web
Log into Outlook on the web in your browser. Open any message from the sender you want to block. At the top right of the message, click the three dots (more actions menu).
Look for an option labeled "Block" or "Block sender". Click it. Outlook will move the message to Junk and add the sender to your blocked list. Any future messages from that address will go directly to Junk without appearing in your inbox.
If you cannot find the block option in the three-dot menu, try clicking "Junk" instead, which may open a submenu with blocking options. The exact wording and menu location can vary depending on which version of Outlook on the web your organization uses.
Block a sender in Outlook mobile apps
Open the Outlook app on your phone or tablet. Find and open any message from the sender you want to block. Tap the three dots or menu icon (usually at the top right of the message).
Select "Block sender" or "Block" from the menu that appears. The sender will be added to your blocked list, and their future messages will go to Junk. On some mobile versions, you may need to tap "Junk" first and then confirm the block.
The exact steps can vary between the Outlook app for iPhone, Android, and iPad, but the general flow is the same: open a message, tap the menu, and select the block option.
Unblock a sender you blocked by mistake
If you blocked someone by mistake, you can unblock them. On desktop Outlook, go to File, then Options, then Trust Center, then Trust Center Settings, then Safe Senders and Blocked Senders. Select the Blocked Senders tab, find the address you want to unblock, select it, and click Remove.
On Outlook on the web, click the Settings gear icon, then "View all Outlook settings", then "Mail", then "Junk email". Under "Blocked senders", find the address and click the X or trash icon next to it to remove the block.
On mobile, the process varies by app version. Generally, you can go to Settings within the Outlook app, find Blocked Senders or Junk settings, and remove the sender from the list. If you cannot find the option, check your app's Help section or update to the latest version.
What happens to messages after you block a sender
Messages that arrive after you block a sender go straight to your Junk folder. Messages from that sender that were already in your inbox before you blocked them stay where they are — blocking does not delete old messages or move them retroactively.
If you want to clean up old messages from a blocked sender, you can select them manually and delete them, or move them to a folder. Blocking only affects new incoming mail.
Blocked senders can still send you messages — they just will not see any sign that you received them, because the messages bypass your inbox and you receive no notification. This is different from marking someone as spam, where Outlook may eventually stop delivering their messages entirely.
Blocking versus marking as spam
Blocking and marking as spam are two different actions in Outlook. When you block a sender, their messages go to Junk but Outlook does not learn anything from your action. When you mark a message as spam (sometimes called "Report Phishing" or "Report Junk"), you tell Outlook that this type of message is unwanted, and Outlook uses that feedback to improve its spam filter for everyone.
If you receive a phishing email or a scam, marking it as spam is more effective than blocking, because it helps Outlook recognize similar messages in the future. If you simply do not want to hear from someone you know, blocking is the right choice.
You can block a sender and mark their message as spam at the same time. The block takes effect immediately, and the spam report goes to Microsoft to help improve the filter.
Frequently Asked Questions
Can a blocked sender tell that I blocked them?
No. A blocked sender can still send you messages, but they will not receive any notification that you blocked them. Their messages simply go to your Junk folder, and you will not see them or get alerts. From their perspective, it looks like their messages are being delivered normally.
Will blocking a sender delete their old messages from my inbox?
No. Blocking only affects new messages going forward. Any messages from that sender that are already in your inbox will stay there. You must delete them manually if you want them gone. To clean up, select the old messages, then delete or move them to a folder.
Can I block an entire domain instead of just one email address?
Outlook does not have a built-in feature to block an entire domain at once. You can only block individual email addresses. If you receive unwanted mail from many addresses at the same domain, you will need to block each one separately, or use Outlook rules to automatically send messages from that domain to Junk.
What is the difference between blocking and creating a rule?
Blocking is quick and works on one sender at a time. Creating a rule is more powerful — you can set rules to automatically delete, move, or flag messages based on sender, subject line, keywords, or other criteria. Rules are useful if you want to organize mail from multiple senders or handle messages in a specific way beyond just sending them to Junk.
If I unblock a sender, will their old messages come back to my inbox?
No. Unblocking a sender only stops the block from applying to new messages. Any messages that went to Junk while the sender was blocked will stay in Junk. You can move them back to your inbox manually if you want to see them again.