Mark a single email as spam in three clicks
Open the email you want to mark as spam. At the top of the message, find the Junk button — it looks like a trash can or prohibition symbol depending on your Outlook version. Click it, then select Junk or Block Sender from the menu that appears. Outlook moves the email to your Junk folder and learns to send future messages from that sender there automatically.
If you use Outlook on the web, the button is in the toolbar above the message. On Outlook desktop (Windows or Mac), it's in the ribbon at the top. On Outlook mobile, swipe left on the email and tap the trash or junk icon, then confirm you want to mark it as junk.
The sender's address goes on your blocked list, but you can undo this at any time by going to Settings and removing them from your blocked senders list.
Key Takeaways
- Click the Junk button on any email and select Junk to move it to your Junk folder and block that sender automatically.
- On Outlook desktop, the Junk button is in the ribbon; on Outlook web, it's in the toolbar above the message.
- Marking an email as spam adds the sender to your blocked list, but you can remove them later if you change your mind.
- Outlook learns from emails you mark as junk and filters similar messages to that folder in the future.
- You can also report phishing emails to Microsoft by selecting Report Phishing instead of just Junk.
Block a sender instead of just marking one email
If you want to block someone completely without waiting for their next email, go to your Outlook settings. On the web version, click the gear icon in the top right, then View all Outlook settings. On desktop, go to File > Options > Trust Center > Trust Center Settings > Safe Senders & Block Senders.
In the Blocked Senders tab, type the email address or domain you want to block, then click Add. From that point on, any email from that address goes straight to Junk. You can add multiple addresses at once by pasting them in, separated by semicolons.
Blocking a domain (like @example.com) stops all email from anyone at that company, which is useful if you're getting spam from multiple addresses at the same organization.
Report phishing and malicious emails to Microsoft
If an email looks like a phishing attempt — asking you to confirm your password, click a suspicious link, or read an attachment — don't just mark it as junk. Report it to Microsoft instead. On Outlook web, click the three dots next to the Junk button and select Report Phishing. On desktop, go to Home > Junk > Report Phishing.
When you report phishing, Microsoft analyzes the email and uses it to improve spam filters for all Outlook users. The email still goes to Junk, but your report helps catch similar attacks before they reach other inboxes.
Never click links or read attachments from suspected phishing emails, even to "confirm" something or "verify" your account. If you're unsure whether an email is real, contact the company directly using a phone number or website you know is legitimate.
Recover emails you marked as spam by mistake
If you marked an email as spam and want it back, go to your Junk folder. Find the email, right-click it, and select Mark as Not Junk or Move to Inbox. On Outlook web, click the email, then click the three dots and choose Mark as Not Junk.
Marking an email as not junk also removes that sender from your blocked list, so their future emails will go to your inbox again. If you want to keep the email but don't want to unblock the sender, just move it to a folder instead of marking it as not junk.
Set up rules to handle spam automatically
For senders you want to filter but not completely block, you can create a rule that sorts their emails into a specific folder. On Outlook desktop, go to Home > Rules > Create Rule. On Outlook web, click the gear icon, then View all Outlook settings > Mail > Rules.
Set the rule to match emails from a specific sender or with certain words in the subject line, then choose where they go — Junk, a custom folder, or even delete them automatically. Rules are useful for newsletters you don't want to unsubscribe from but also don't want cluttering your inbox.
You can create as many rules as you need, and they explore to new emails going forward, not to messages already in your inbox.
Understand the difference between Junk and Deleted folders
When you mark an email as spam, it goes to your Junk folder, not your Deleted Items folder. Junk is where Outlook stores suspected spam; Deleted Items is where emails go when you delete them manually. The two folders work differently.
Emails in Junk stay there for 30 days before Outlook deletes them permanently. Emails in Deleted Items stay for 30 days as well, but you can recover them more easily because they're not mixed with actual spam. If you delete an email by mistake, check Deleted Items first.
If you want to permanently delete a spam email instead of letting it sit in Junk, open it and press Delete, or right-click it in Junk and select Delete.
Frequently Asked Questions
Does marking an email as spam tell the sender I blocked them?
No. Marking an email as spam only affects your inbox — the sender has no way to know. They won't receive a notification, and their email address isn't flagged anywhere. They can keep sending you emails, but Outlook will filter them to Junk automatically.
Can I mark an entire conversation as spam?
On Outlook web, you can select multiple emails from the same sender and mark them all as junk at once. On desktop, you can do the same by holding Ctrl (or Cmd on Mac) and clicking each email, then clicking Junk. However, blocking the sender is usually faster if you want to stop all their future emails.
What happens if I mark an email as spam but the sender is in my contacts?
Outlook will still move it to Junk and block them. If you want to keep receiving emails from someone in your contacts, don't mark their emails as spam — instead, move them to a folder or create a rule. You can always unblock them later from your blocked senders list.
Why are legitimate emails ending up in my Junk folder?
Outlook's spam filter sometimes catches real emails by mistake, especially from newsletters or automated notifications. Check your Junk folder regularly and mark important emails as not junk. You can also add trusted senders to your Safe Senders list in Settings to prevent this.
Can I undo blocking a sender?
Yes. Go to Settings, find your blocked senders list, and remove the address. Their future emails will go to your inbox again. You can also mark one of their emails as not junk, which automatically removes them from your blocked list.