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Microsoft Defender for Office 365 Reviews

Vendor: Microsoft
4.2 out of 5
Badge Ranked 1
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What is Microsoft Defender for Office 365?

Microsoft Defender for Office 365 is a comprehensive security solution designed to protect organizations against advanced threats in their email, collaboration, and productivity environments. It combines the power of Microsoft's threat intelligence, machine learning, and behavioral analytics to provide real-time protection against phishing, malware, ransomware, and other malicious attacks.

Get the Microsoft Defender for Office 365 Buyer's Guide and find out what your peers are saying about Microsoft Defender for Office 365, Microsoft Intune, Microsoft Defender for Endpoint and more!
Microsoft Defender for Office 365 is the #1 ranked solution in top Email Archiving solutions, #1 ranked solution in top Email Security solutions, #1 ranked solution in top Secure Email Gateway (SEG) solutions, #2 ranked solution in top Advanced Threat Protection (ATP) solutions, and #10 ranked solution in top Microsoft Security Suite solutions. PeerSpot users give Microsoft Defender for Office 365 an average rating of 8.4 out of 10. Microsoft Defender for Office 365 is most commonly compared to Microsoft Intune: Microsoft Defender for Office 365 vs Microsoft Intune. Microsoft Defender for Office 365 is popular among the large enterprise segment, accounting for 46% of users researching this solution on PeerSpot. The top industry researching this solution are professionals from a computer software company, accounting for 15% of all views.
Buyer's Guide
Microsoft Defender for Office 365
December 2025
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Helped 879,259 peers since 2012

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Microsoft Defender for Office 365 mindshare

Product category:
Email Security
As of December 2025, the mindshare of Microsoft Defender for Office 365 in the Email Security category stands at 10.4%, down from 14.4% compared to the previous year, according to calculations based on PeerSpot user engagement data.
Email Security Market Share Distribution
ProductMarket Share (%)
Microsoft Defender for Office 36510.4%
Proofpoint Email Protection7.7%
Abnormal Security6.0%
Other75.9%
Email Security

PeerResearch reports based on Microsoft Defender for Office 365 reviews

TypeTitleDate
CategoryEmail SecurityDec 29, 2025Download
ProductReviews, tips, and advice from real usersDec 29, 2025Download
ComparisonMicrosoft Defender for Office 365 vs Check Point Harmony Email & CollaborationDec 29, 2025Download
ComparisonMicrosoft Defender for Office 365 vs Proofpoint Email ProtectionDec 29, 2025Download
ComparisonMicrosoft Defender for Office 365 vs Abnormal SecurityDec 29, 2025Download
Suggested products
TitleRatingMindshareRecommending
Microsoft Intune4.1N/A94%305 interviewsAdd to research
Microsoft Defender for Endpoint4.1N/A95%210 interviewsAdd to research
 
 
Key learnings from peers
Last updated Nov 21, 2025

Valuable Features

Microsoft Defender for Office 365 offers strong features like anti-phishing, anti-malware, and Safe Links, providing efficient email threat detection and prevention. Its ease of use, seamless integration, and prioritization capabilities enhance threat management. Protection extends to data loss prevention policies and information security across Office 365 applications, with valuable insights from endpoint management and threat intelligence. Organizations benefit from visibility into threats, proactive threat simulation, and improved security operations with minimal setup.
  • "The feature I like the most about Microsoft Defender for Office 365 is that it typically runs in the background—you do not know it is there until you need to access it."
  • "The coolest feature of Microsoft Defender for Office 365 is its ability to look for phishing emails."
  • "The features I appreciate most about Microsoft Defender for Office 365 are admin notifications for potential threats along with protecting our Microsoft apps such as Outlook from potential phishing attacks."

Room for Improvement

Microsoft Defender for Office 365 faces challenges in scalability, pricing, and licensing. It requires better integration with external apps and improved user interface. False positives are frequent in phishing and spam detection. The absence of proactive threat alerts and custom notifications limits its effectiveness. Reports lack depth, and data loss prevention is restricted. Documentation and support need enhancement. Its protection on non-Windows systems and handling of non-Microsoft file types lag behind competitors.
  • "From a development point of view, if I wanted to do development on my actual machine where Defender is, the organization can set certain policies or Defender makes that prohibitive."
  • "Sometimes I have to recategorize things when it takes the wrong step and I do not want it to classify something as suspicious."
  • "To improve Microsoft Defender for Office 365, it would be nice to have more accessibility for users to see on their end what they are doing that could cause a threat."

ROI

Several users express that Microsoft Defender for Office 365 provides a valuable return on investment, primarily in reducing security risks and operational costs. They highlight its effectiveness in enhancing email protection and improving security, despite some challenges in quantifying exact returns. Many note the savings compared to alternatives, reduced time spent on security tasks, and its bundled cost benefits, leading to better resource allocation and enhanced productivity.

Pricing

Microsoft Defender for Office 365 pricing varies, tied to Microsoft 365 subscriptions like E3 and E5, often requiring an add-on for specific features. Users describe it as expensive, particularly for small and medium enterprises, but its integration with Microsoft's ecosystem is advantageous. Some find the cost justified by enhanced security and productivity gains. Licensing complexity is noted, with options for monthly or annual payments. It's seen as reasonable compared to similar enterprise security solutions, yet cost concerns persist.
  • "While Microsoft Defender for Office 365 necessitates pricier E3 or E5 subscriptions, the extensive functionality offered by these licenses across various Microsoft products justifies the investment."
  • "I know that the product is incredibly expensive."
  • "The product is very expensive."

Popular Use Cases

Organizations primarily use Microsoft Defender for Office 365 for email security, protecting against phishing, spam, and malicious attachments. It secures Office tools, monitors user behavior, and protects endpoint and identity security. Microsoft Defender is also deployed for data loss prevention, compliance tasks, and reports on vulnerabilities. Many leverage its integration with Azure and Microsoft Sentinel, using it to safeguard cloud and on-premises environments across diverse industries.

Service and Support

Users highlight Microsoft's technical support for Defender as mostly responsive and knowledgeable, although experiences vary based on the level of support purchased. Premier support is praised for quick responses, while lower levels may lead to slower resolutions. Documentation is detailed but can be outdated, creating complexities. When contacting support, users report mixed experiences, with some changes in support models leading to dissatisfaction. Users with premium contracts report better satisfaction and rapid issue resolution.

Deployment

Many found Microsoft Defender for Office 365's initial setup straightforward due to its cloud-based nature, requiring minimal staff. Most could handle configuration easily, with some outsourcing to IT teams. Documentation from Microsoft was helpful. Deployment could be quick, though larger enterprises faced complexities. Once familiar, deployment became smoother. Users noted the importance of fine-tuning settings post-deployment and found the setup integrated well with Office 365, making it convenient for both SMBs and enterprises.

Scalability

Microsoft Defender for Office 365 demonstrates a high level of scalability. Various users have deployed it to thousands of accounts without performance issues. The cloud-based nature allows seamless expansion by simply adding licenses. Adjustments like bandwidth considerations are needed for optimal scaling, especially in hybrid or multi-geographic environments. Microsoft's investment in scalability ensures efficient handling of increasing cybersecurity needs. Users rate it highly for its effectiveness across diverse organizational structures. Scalability remains transparent and adaptable.

Stability

Microsoft Defender for Office 365 is generally stable with high availability, boasting a 99.9% uptime guarantee. Users report occasional bugs but find them rectifiable, resulting in minimal disruptions. Some experience rare outages and fluctuating services, yet most indicate seamless cloud updates without major downtime. False positives occur, necessitating configuration adjustments. Ratings frequently highlight stability, scoring mostly between eight and ten. Concerns related to Microsoft Teams reflect variability, though not directly impacting Microsoft's Defender.
These insights are based on the in-depth reviews provided by peers to help you make a better buying decision.
Download our Microsoft Defender for Office 365 Buyer's Guide for additional reliable information.

Review data by company size

By reviewers
Company SizeCount
Small Business21
Midsize Enterprise9
Large Enterprise28
By reviewers
By visitors reading reviews
Company SizeCount
Small Business1988
Midsize Enterprise1095
Large Enterprise2595
By visitors reading reviews

Top industries

By visitors reading reviews
Computer Software Company
15%
Financial Services Firm
8%
Manufacturing Company
8%
Comms Service Provider
6%
Government
5%
Healthcare Company
5%
Construction Company
5%
Retailer
5%
University
4%
Educational Organization
4%
Insurance Company
3%
Real Estate/Law Firm
3%
Outsourcing Company
3%
Legal Firm
3%
Energy/Utilities Company
3%
Performing Arts
2%
Hospitality Company
2%
Wholesaler/Distributor
2%
Non Profit
2%
Media Company
2%
Transportation Company
1%
Consumer Goods Company
1%
Recreational Facilities/Services Company
1%
Pharma/Biotech Company
1%
Logistics Company
1%
Marketing Services Firm
1%

Compare Microsoft Defender for Office 365 with alternative products

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Learn more about Microsoft Defender for Office 365

With Microsoft Defender for Office 365, organizations can safeguard their email communication by detecting and blocking malicious links, attachments, and unsafe email content. It employs advanced anti-phishing capabilities to identify and prevent sophisticated phishing attacks that attempt to steal sensitive information or compromise user credentials.

This solution also offers robust protection against malware and ransomware. It leverages machine learning algorithms to analyze email attachments and URLs in real-time, identifying and blocking malicious content before it reaches users' inboxes. Additionally, it provides advanced threat-hunting capabilities, allowing security teams to proactively investigate and respond to potential threats.

Microsoft Defender for Office 365 goes beyond email protection and extends its security features to other collaboration tools like SharePoint, OneDrive, and Teams. It scans files and documents stored in these platforms, ensuring that they are free from malware and other malicious content. It also provides visibility into user activities, helping organizations detect and mitigate insider threats.

Furthermore, this solution offers rich reporting and analytics capabilities, providing organizations with insights into their security posture and threat landscape. It enables security administrators to monitor and manage security incidents, track trends, and take proactive measures to enhance their overall security posture.

Microsoft Defender for Office 365 was previously known as MS Defender for Office 365.

Microsoft Defender for Office 365 customers

Microsoft Defender for Office 365 is trusted by companies such as Ithaca College.

Related questions

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  • 45
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  • 31
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When evaluating Email Security tools, what aspects do you think are the most important to look for?

Product Categories

Product Categories
Email Security
Email Archiving
Advanced Threat Protection (ATP)
Microsoft Security Suite
Secure Email Gateway (SEG)

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Microsoft Defender for Office 365 Reviews Summary
Author infoRatingReview Summary
Cloud Solutions Architect at a tech services company with 201-500 employees5.0I've used Microsoft Defender for Office 365 for five years to protect emails, documents, and users from threats; it's stable, easy to deploy, improves threat visibility, and the attack simulation and response features are especially valuable.
Manager at a tech services company with 10,001+ employees3.5I've used Microsoft Defender for Office 365 extensively; it's insightful and integrates well with E5 licensing, but its cloud security lags behind competitors like Wiz and Palo Alto. Support and costs vary depending on the subscription model.
Senior Client Director and Advisory Service Leader at Crossfuze4.0Microsoft Defender for Office 365 protects well against phishing and malware, saves time, and reduces help desk calls. It's reliable and scalable, though Security Copilot costs are high. Setup is easy, and threat intelligence supports proactive incident response.
Senior Director, Security Architecture & Engineering at a leisure / travel company with 10,001+ employees4.5I use Microsoft Defender for Office 365 primarily for email, device, and identity security. Its improved anti-phishing features have reduced incidents and costs. However, navigating the multiple consoles is challenging. Prior solutions like McAfee were costlier and less user-friendly.
Designation Chief Consultant at Avtow4.0I use Microsoft Defender for Office 365 primarily for endpoint security. It offers robust threat response, threat visibility, and cost efficiency as part of the Microsoft 365 bundle. However, I believe the DLP capabilities could be improved.
Inside Solutions Architect at a retailer with 1,001-5,000 employees4.0I use Microsoft Defender for Office 365 mainly for email security, value its anti-impersonation and automation features, and find it reliable and cost-effective, though I’d like to see improved AI-driven threat prediction capabilities.
Head of Development at a consultancy with 1,001-5,000 employees4.0I've found Microsoft Defender for Office 365 reliable and unobtrusive, offering strong background protection and easy file scanning, though it can hinder development work due to strict policies. Overall, it's effective and centrally managed for consistent security.
Chief Architect at a tech vendor with 1,001-5,000 employees4.5We find the DLP feature of Microsoft Defender for Office 365 valuable for protecting sensitive data, but we encounter false positives that confuse users. While security is crucial for us as a public company, quantifying ROI remains challenging. We rely on Microsoft Azure.