How to Attach an Email to an Email in Outlook

Attaching one email to another sounds simple, but Outlook gives you several ways to do it — and the right method depends on what you're actually trying to accomplish. Whether you want to forward a message as a file, bundle multiple emails into one send, or preserve the original formatting intact, knowing your options matters.

Why Attach an Email Instead of Just Forwarding It?

When you forward an email, Outlook pastes the original message content into the body of a new email. That works fine for simple threads, but it has limitations:

• The formatting can break or get messy with long chains
• Attachments from the original message don't always carry over cleanly
• The recipient sees everything inline, which can be hard to parse
• You can't forward multiple separate emails in a single action using the standard forward button

Attaching an email as a file (specifically as a .msg file in Outlook) keeps the original message completely intact — headers, timestamps, attachments, and all. The recipient opens it like any other attachment and sees the email exactly as it was received.

This matters in professional or legal contexts where preserving the original message structure is important.

Method 1: Drag and Drop an Email Into a New Message 🖱️

This is the fastest method and works in the Outlook desktop app on Windows.

1. Open a new email (or a reply/forward you're composing)
2. Go back to your inbox or folder and find the email you want to attach
3. Click and drag that email from the message list directly into the body of your new message
4. Release — it appears as a .msg attachment

The dragged email becomes a proper file attachment, not an inline quote. Recipients can double-click it to open the full original message in Outlook.

Works best when: You're on a desktop, using the full Outlook application, and need a quick one-off attachment.

Method 2: Use "Forward as Attachment"

Outlook has a built-in option specifically for this purpose.

1. Select the email you want to attach (click it once in your inbox)
2. Go to the Home tab in the ribbon
3. Click the dropdown arrow next to the "Forward" button
4. Select "Forward as Attachment"

This opens a new compose window with the original email already attached as a .msg file. You then address it and add any message in the body as you normally would.

Keyboard shortcut:Ctrl + Alt + F on Windows opens the "Forward as Attachment" option directly.

Works best when: You want a clean, deliberate method without drag-and-drop.

Method 3: Attach Multiple Emails at Once

If you need to send several emails as attachments in a single message — useful for escalating a thread or submitting documentation — the drag-and-drop method scales up easily.

1. Open your new compose window
2. In your inbox, select multiple emails using Ctrl + Click (individual selection) or Shift + Click (range selection)
3. Drag the entire selection into your compose window
4. All selected emails appear as individual .msg attachments

This is one of the less obvious but genuinely useful features of the Outlook desktop app. There's no equivalent one-step method in Outlook on the web for multiple attachments.

Method 4: Attach an Email in Outlook on the Web (OWA)

The web version of Outlook (outlook.com or the Microsoft 365 web app) handles this differently because drag-and-drop from the message list doesn't work the same way.

Options available in OWA:

• Use the "Forward as attachment" option by right-clicking a message in your inbox and selecting it from the context menu (availability depends on your version)
• Download the email as a .eml or .msg file first, then attach it to a new message using the standard attachment button
• Some Microsoft 365 organizational accounts expose additional options through the three-dot menu on a message

The web app experience varies more than the desktop app, and not all features are present in all account types.

Method 5: Attach an Email in Outlook for Mac

Outlook for Mac supports drag-and-drop similarly to Windows:

1. Open a new compose window
2. Drag an email from your message list into the body of the new message
3. It attaches as a .msg or .eml file depending on your version

"Forward as Attachment" is also available via the Message menu at the top of the screen, or by right-clicking the email in your list.

What the Recipient Sees

.msg files are a Microsoft-proprietary format. Recipients using non-Outlook email clients (like Apple Mail or Gmail) may have trouble opening them directly, though third-party tools exist for this. .eml files have broader compatibility across email clients and platforms.

Factors That Affect Which Method Works for You

Several variables shape which approach is actually available and practical:

• Desktop app vs. web app — the full Outlook desktop application offers more options than OWA
• Windows vs. Mac — minor differences in menu placement and keyboard shortcuts
• Outlook version — Microsoft 365 subscribers get more frequent feature updates than perpetual license users (e.g., Outlook 2019, 2021)
• Organizational account vs. personal account — corporate Microsoft 365 tenants may have admin-controlled settings that affect available features
• Recipient's email client — if they're not using Outlook, .msg attachments may not open correctly

The method that's frictionless for one person's setup might be unavailable or awkward for another's — and that's before accounting for whether the recipient can actually open what you send them.