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Microsoft Office 365, branded as "Cowboy Mail" is the email system used by OSU students, faculty, and staff. Microsoft Office 365 also includes access to other Microsoft applications and services.


OSU email addresses always end in “” and are where university communications are sent. Users may also access other Microsoft® Office 365™ services like Word or PowerPoint. Students retain their “” email address after graduation.

Getting Started

  1. To access Cowboy Mail, visit

  2. Enter your OSU Email address.The sign-in screen for cowboy mail where you input your email address.

  3. After typing in your email address, you will be prompted for a password.The sign-in screen for cowboy mail where you input your password.

  4. If you have multi-factor authentication enabled on your account, you may be prompted with this screen before advancing. Choose your preferred authentication method to verify your identity.
    The multi-factor authentication form that tries to confirm your identity.

  5.  You will now be signed into your Cowboy Mail account.


Available to

Role Stillwater

External Email Warning

When receiving an email from outside of the OSU domain, you will receive the following warning message at the top of the email:


“CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.”

New Warning 

Older emails from before May 11th, 2020 may display this message instead:

“**External Email – Please verify sender email address before responding.**”


If you believe this message is Spam or a Phishing Attempt, please forward the email to for further assistance.

Frequently Asked Questions (FAQ)

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