Microsoft Defender for Office 365 review

Defender for Office 365 earns the top spot because it gives Microsoft 365 tenants a large step up in phishing defense for very little money. Plan 1, at $2 per user per month paid yearly, adds real-time checks on links and QR codes, detonation of attachments for zero-day malware, language model based analysis aimed at phishing and BEC, and protection for internal mail. It covers Teams, SharePoint and OneDrive, which matters as attackers move into chat and shared files. Plan 2, at $5, adds threat hunting, campaign tracking, attack simulation training and automated investigation and response, plus cross-domain hunting in Defender XDR. Microsoft also publishes its own detection performance data, which helps when you compare it with third-party tools. The limits are scope and complexity: it does nothing for Google Workspace, and tuning its policies across Microsoft's admin portals takes practice. Specialist tools still catch some BEC it misses, so many teams layer one on top, but for most Microsoft 365 shops this is where to start.

Who it is for

Organizations on Microsoft 365 that want strong phishing protection at the lowest per user price, managed from the same console as the rest of their Microsoft security.

Price

Plan 1 from $2 per user per month paid yearly; Plan 2 $5 per user per month.

$2.00 user/month, paid yearly
Quoted from the vendor pricing page on November 9, 2026.

Key features

• Real-time protection for malicious links and QR codes
• Zero-day malware and virus protection for attachments
• Language model based sentiment analysis against phishing and BEC
• Protection across email, Teams, SharePoint and OneDrive, including internal email
• Plan 2 adds threat hunting, attack simulation training and automated investigation and response

Strengths and weaknesses

• Strength: Plan 1 costs $2 per user per month, the lowest published price here for API-level Microsoft 365 protection
• Strength: Covers Teams, SharePoint and OneDrive as well as mailboxes
• Strength: Plan 2 links email incidents with endpoint and identity data in Defender XDR
• Weakness: Only protects Microsoft 365; no Google Workspace coverage
• Weakness: Attack simulation training and automated response need Plan 2
• Weakness: Policy settings spread across several Microsoft portals take time to learn

Key facts

• Plans: Plan 1, Plan 2, Microsoft Defender Suite
• Plan 2 price: $5 per user per month, paid yearly
• Platforms: Microsoft 365 email, Teams, SharePoint, OneDrive
• Free trial: Yes, on Plan 1 and Plan 2

Where it ranks

Microsoft Defender for Office 365 is No. 1 in our Best Email Security Software verdict.