How to Set Up Email Filters in Thunderbird

Updated March 2026 · 6 min read

Message filters are one of Thunderbird's most powerful features. They let you automatically sort, tag, forward, or delete emails based on rules you define — saving you hours of manual inbox management every week.

What Are Message Filters?

A message filter is a rule that runs automatically when messages arrive (or when you manually trigger it). For example: "If the sender is [email protected], move the message to the Newsletters folder and mark it as read."

Step 1: Open the Message Filters Window

In Thunderbird, go to Tools → Message Filters (on Mac: Thunderbird menu → Message Filters). This opens the Filters window showing all your current filters.

Step 2: Create a New Filter

Click the New button. The Filter Rules dialog will open. At the top, give your filter a descriptive name — for example "Sort Newsletters".

Step 3: Set Your Match Conditions

Under "For incoming messages that:", choose your match criteria:

• From — matches the sender's email or name
• Subject — matches words in the subject line
• To — matches the recipient address
• Body — matches words in the message body
• Date — matches messages by date range

You can add multiple conditions and choose "Match all of the following" (AND logic) or "Match any of the following" (OR logic).

Step 4: Choose Actions

Under "Perform these actions:", define what happens to matched messages:

• Move to Folder — moves the message to a specified folder
• Copy to Folder — keeps original and copies to another folder
• Mark as Read — automatically marks messages as read
• Add Tag — applies a colored tag label
• Delete Message — permanently deletes
• Forward to — auto-forwards to another email address
• Run Add-on Action — triggers a plugin if installed

Step 5: Save and Test

Click OK to save the filter. Back in the Filters window, you can click Run Now to apply the filter to messages already in your inbox.

Practical Filter Examples

• Auto-archive newsletters: From contains "unsubscribe" → Move to Newsletters folder, Mark as Read
• Priority boss emails: From is your manager's email → Tag "Important", Play Sound
• Block spam: Subject contains "URGENT" or "free offer" → Delete Message
• Work/personal separation: To contains [email protected] → Move to Work folder

Tips

Filters run in order — drag them to reorder. If one filter moves a message, subsequent filters may not see it depending on your "Stop executing more filters" setting. Use this to prevent conflicts.