How to Block Someone in Outlook (Junk + Rules 2026)

Blocking someone in Outlook adds their email address to the Blocked Senders list. Future emails from them route directly to the Junk folder instead of your Inbox. Junk auto-deletes after 30 days so you never see the messages. Here is how to block a sender in Outlook desktop, web, and mobile in 2026, plus how to block entire domains and unblock later.

Block a sender in Outlook desktop (classic Windows)

1. Open Outlook.
2. Right-click the email from the sender you want to block.
3. Hover over Junk in the menu.
4. Click Block Sender.
5. Outlook confirms with a dialog. Click OK.

The sender is added to your Blocked Senders list. Future emails go directly to the Junk folder.

Block a sender in New Outlook and Outlook Web

1. Open New Outlook or sign in to outlook.office.com.
2. Right-click the email OR click the three-dot menu at the top of the message.
3. Click Block → Block sender.
4. Confirm by clicking OK.

Block a sender in Outlook mobile (Android and iPhone)

1. Open the Outlook app.
2. Open the email from the sender.
3. Tap the three-dot menu at the top-right of the message.
4. Tap Move to Junk or Block sender (label depends on app version).
5. Confirm.

Manually add someone to Blocked Senders (before receiving an email)

Classic desktop:

1. Click Home tab → Junk → Junk Email Options.
2. Click the Blocked Senders tab.
3. Click Add.
4. Type the email address to block (or entire domain: @spamdomain.com).
5. Click OK twice to save.

Outlook Web:

1. Settings → View all Outlook settings → Mail → Junk email.
2. Under “Blocked senders and domains”, click Add.
3. Enter email address or domain.
4. Click Save.

Block an entire domain in Outlook

Blocking a whole domain stops emails from every address ending in that domain (like all emails from @spamnews.com).

1. Follow the manual add steps above.
2. Instead of a full email address, enter just the domain with @ prefix: @example.com.
3. Save.

All future emails from any address at that domain are routed to Junk automatically.

Unblock a sender in Outlook

Classic desktop:

1. Home tab → Junk → Junk Email Options.
2. Blocked Senders tab.
3. Select the address or domain in the list.
4. Click Remove.
5. Click OK.

Outlook Web:

1. Settings → View all Outlook settings → Mail → Junk email.
2. Under Blocked senders, click the trash icon next to the address.
3. Save.

Block vs Rules vs Junk filter: which to use

• Block Sender: routes future emails to Junk. Simple but per-address only. Not-quite-instant on some setups.
• Rules: more powerful. Can filter by subject, keywords, attachment, size, and combine multiple conditions. Rules can delete instantly, forward, or mark.
• Junk Email Filter: Microsoft’s automatic spam detection. Runs before your rules. Marks emails as junk based on reputation and content signals.
• Recommendation: use Block Sender for personal contacts you no longer want to hear from. Use Rules for pattern-based filtering. Trust the Junk filter for spam that Microsoft catches automatically.

Common Outlook blocking problems

• Blocked sender still lands in Inbox: Outlook may be caching. Restart Outlook. Or check that “Safe Senders” list does not include this address (Safe Senders override Blocked Senders).
• Emails from mailing list still arrive: mailing lists send from rotating addresses. Block by domain instead of specific address. Or unsubscribe at the source.
• Blocked but I want to unblock without opening Junk: use the Blocked Senders list in Junk Email Options. You do not need to open the Junk folder to manage the list.
• Cannot block sender – option missing: some corporate Exchange setups disable client-side blocking. Contact IT for organizational-level blocklist.

Common Outlook mistakes to avoid

• Not using folders and rules. An Outlook inbox with 5,000 unread emails is unmanageable. Set up folders per project and rules to auto-file routine mail.
• Forgetting the Signature preview before sending. Signatures render differently across clients. Send yourself a test to catch layout issues before external recipients see them.
• Ignoring Focus Inbox. Outlook’s Focus Inbox auto-filters non-priority mail. Not perfect but a huge time saver once trained.
• Overusing Reply All. The workplace curse. Reply only to the sender unless everyone truly needs the response.
• Not linking Outlook to Teams/OneNote. Microsoft 365 integrations turn Outlook into a hub. Enable calendar-to-Teams and email-to-OneNote linking.

Power-user tips for Outlook

• Use Quick Steps. One-click multi-action shortcuts. Common Quick Step: “File to Project X + mark as read + reply with template”.
• Master search operators. from:name, subject:keyword, hasattachments:yes, received:this-week. Combine for laser-focused inbox search.
• Delay all sends by 60 seconds. File > Options > Mail > Delivery. Prevents accidental sends. Set to 1 minute; retract by editing outgoing.
• Set up conditional formatting for VIPs. Emails from your boss appear in red. Instant priority visibility.
• Use categories, not folders, for tagging. Categories work across folders. A “Follow-up” category surfaces across your entire mailbox.

Outlook desktop vs web vs mobile

Outlook desktop (Windows/Mac) has the most features: full rules engine, advanced search, offline access. Best for heavy email users.

Outlook Web App (OWA) works from any browser. Rules and rules editor slightly limited compared to desktop. Search is fast because it hits the server directly.

Outlook mobile (iOS/Android) is streamlined for on-the-go. Swipe gestures customizable. Good for triage; not ideal for composing long emails.

For most professionals, desktop for morning triage, mobile for meetings, web for occasional access from unfamiliar computers. Sync happens instantly across all three.

Best practices summary

• Zero-inbox mindset. Every email gets a decision: reply, defer, delegate, or delete. No email stays “read but not decided”.
• Rules for routine mail. Newsletter to Reading folder. Reports to Reports folder. Approvals to Approvals folder. Never manually file the same type twice.
• Categorize actively. Follow-up, waiting-for, this-week. Categories cross folder boundaries.
• Schedule email review windows. Not constant checking. Two focused sessions per day beat 40 distracted glances.
• Archive, do not delete. Storage is cheap. Full-text search is powerful. Archive lets you find anything years later.