Block a sender in Outlook in three steps
Open the email from the person you want to block. Click the three dots (more actions menu) at the top right of the message. Select Block from the dropdown menu. Outlook will move that sender's future emails to your Junk folder automatically.
If you have already deleted the email, you can still block the sender. Go to Settings (the gear icon), then Mail, then Junk email. Under "Blocked senders", add the email address manually. Any email from that address will go straight to Junk from that point forward.
Blocking works the same way whether you use Outlook on the web, the desktop app for Windows, or Outlook on Mac. The blocked sender cannot tell that you have blocked them — they will not receive a notification, and their emails straightforward will not reach your inbox.
Key Takeaways
- You can block a sender directly from an open email by clicking the three-dot menu and selecting Block.
- Blocked emails go to your Junk folder, not deleted, so you can review them later if you change your mind.
- You can unblock a sender at any time by going to Settings > Mail > Junk email and removing them from the Blocked senders list.
- Blocking a sender does not delete their past emails — only stops new ones from reaching your inbox.
What happens when you block someone
Once you block an email address, every message from that sender goes to your Junk folder instead of your inbox. This means you will not see a notification when they email you, and their messages will not clutter your main view. The emails are not deleted — they stay in Junk for 30 days before Outlook removes them automatically.
If you block someone by mistake, or if you change your mind later, you can unblock them. Go to Settings > Mail > Junk email, find their address in the "Blocked senders" list, and click the X next to their name. Their future emails will then go to your inbox again.
When to block versus when to report
Blocking is the right choice when someone you know is sending unwanted emails — a person who keeps emailing after you have asked them to stop, or someone whose messages you straightforward do not want to see. Blocking removes them from your inbox without any further action.
Reporting is different and serves a different purpose. If an email looks like a scam, phishing attempt, or spam from an unknown sender, report it instead of just blocking. Click the three-dot menu and select Report phishing or Report junk. This tells Microsoft about the email so they can improve their filters and protect other users. You can both report and block the same sender — reporting does not prevent their emails from reaching you, but blocking does.
If you receive threatening, harassing, or abusive emails, consider reporting to law enforcement in addition to blocking. Outlook's block feature is a privacy tool, not a safety tool for serious threats.
Block an entire domain or email pattern
Outlook's block feature works on individual email addresses, not on entire domains. If you are getting spam from multiple addresses at the same company (like noreply@spamcompany.com, support@spamcompany.com, and sales@spamcompany.com), you will need to block each address separately.
For a more powerful filter, use Outlook's Rules feature. Go to Settings > Mail > Rules and create a new rule. You can set it to automatically move emails to Junk if they come from a specific domain, contain certain words, or match other patterns. This is more flexible than blocking but requires a few extra steps to set up.
Blocked senders list fills up — what to do
Outlook does not have a hard limit on how many senders you can block, but a very long blocked list can slow down your email performance slightly. If you have blocked dozens of addresses and no longer need to block some of them, clean up your list periodically.
Go to Settings > Mail > Junk email and review your "Blocked senders" list. Remove addresses you no longer need to block. If you are blocking a lot of similar senders (many from the same domain, for example), consider using a Rule instead, which is more efficient.
Block someone on mobile Outlook
On the Outlook mobile app for iPhone or Android, blocking works slightly differently. Open an email from the sender you want to block. Tap the three dots at the top right, then tap Block sender. The app will move their future emails to Junk.
To see your blocked senders list on mobile, go to Settings > Mail > Junk email. The process is the same as on desktop, but the menu layout is slightly different because of the smaller screen.
Frequently Asked Questions
Can a blocked sender tell that I blocked them?
No. Blocked senders receive no notification. Their emails straightforward go to your Junk folder, and they have no way to know whether you blocked them, marked them as spam, or straightforward did not read their message.
If I block someone, do their old emails disappear?
No. Blocking only affects new emails from that sender. Any messages they sent before you blocked them stay in your inbox or other folders. If you want to remove their old emails, you will need to delete them manually or use a rule to move them.
What is the difference between blocking and marking as spam?
Blocking moves a sender's emails to Junk. Marking as spam does the same thing and also tells Microsoft that the sender is a spammer, which helps improve filters for everyone. For unknown senders or obvious scams, marking as spam is usually better. For people you know, blocking is cleaner.
Can I block emails by subject line or content instead of sender?
The Block feature only works on sender addresses. To block by subject line, content, or other patterns, use Rules instead. Go to Settings > Mail > Rules and create a rule that moves emails to Junk based on whatever criteria you choose.
If I unblock someone, will their old emails come back to my inbox?
No. Unblocking only stops new emails from going to Junk. Their old emails stay wherever they are — if they were in Junk, they stay in Junk. You would need to move them manually if you want them back in your inbox.