Microsoft Defender for Office 365
Microsoft's native email security for Microsoft 365 with XDR integration
ToolEmail SecurityCloud
Pricing: Plan 1 $2.00/user/month, paid yearly / Plan 2 $5.00/user/month, paid yearly / included in Microsoft 365 E5
Reviewed by the Cyber Vendor Guide editorial team against the public sources cited below · Last reviewed September 2026 · How we review listings
What is Microsoft Defender for Office 365?
Microsoft Defender for Office 365 is Microsoft's native email security solution that provides protection against phishing, malware, and business email compromise for Microsoft 365 environments. It integrates deeply with the Microsoft security ecosystem including Microsoft Sentinel, Defender XDR, and Entra ID to provide cross-domain threat detection and automated investigation. For organizations heavily invested in Microsoft 365, Defender for Office 365 offers strong protection without requiring a third-party email security gateway.
Best for: Microsoft 365-centric organizations wanting native email security with XDR integration and cost efficiency through E5 licensing
Pros
- Deep native integration with Microsoft 365 and Defender XDR ecosystem
- Included in Microsoft 365 E5. Significant cost savings for E5 customers
- Automated investigation and response reduces analyst workload
- Cross-domain detection correlates email threats with identity and endpoint signals
- Continuous improvement from Microsoft's massive threat intelligence network
Things to check
- Only protects Microsoft 365. Does not support Google Workspace or other platforms
- Detection efficacy for advanced threats historically behind Proofpoint and Mimecast
- Configuration complexity across multiple Microsoft security portals
- Plan 1 lacks important features like AIR and Threat Explorer
- Less effective at catching novel social engineering attacks
Reported in public reviews and vendor documentation. See sources below.
Key Features
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Microsoft Defender for Office 365 Comparisons
- Microsoft Defender for Office 365 vs Acronis Email Security
- Microsoft Defender for Office 365 vs Abnormal AI
- Microsoft Defender for Office 365 vs Barracuda Email Security
- Microsoft Defender for Office 365 vs IRONSCALES
- Microsoft Defender for Office 365 vs Tessian
- Microsoft Defender for Office 365 vs Cisco Secure Email
- Microsoft Defender for Office 365 vs Mimecast
- Microsoft Defender for Office 365 vs Trend Micro Email Security
- Microsoft Defender for Office 365 vs Proofpoint
Sources & references
Where the information on this listing comes from. Always verify pricing and capabilities against the vendor before a purchasing decision.
Spot an error, or do you represent Microsoft Defender for Office 365? Request a correction.
Key facts
- Pricing
- Plan 1 $2.00/user/month, paid yearly / Plan 2 $5.00/user/month, paid yearly / included in Microsoft 365 E5
- Model
- Per-user subscription (bundled with Microsoft 365 E5)
- Founded
- 2015
- Cloud
- Yes
- Self-hosted
- No
Microsoft Defender for Office 365 Alternatives
- ProofpointEnterprise email security platform for advanced threat prote...
- MimecastCloud email security platform with threat protection, archiv...
- Abnormal AIAI-powered email security platform specializing in behaviora...
- Barracuda Email SecurityEmail threat protection platform available as gateway applia...
- Cisco Secure EmailEnterprise email security gateway with Cisco Talos threat in...