# Cisco Secure Email Threat Defense vs Microsoft Defender for Office 365: side-by-side comparison (2026) [Cisco Secure Email Threat Defense](https://cybersectools.com/tools/cisco-secure-email-threat-defense) is a commercial [email security platforms](https://cybersectools.com/categories/email-security-platforms) solution by [Cisco](https://cybersectools.com/companies/cisco). [Microsoft Defender for Office 365](https://cybersectools.com/tools/microsoft-defender-for-office-365) is a commercial [email security platforms](https://cybersectools.com/categories/email-security-platforms) solution by [Microsoft](https://cybersectools.com/companies/microsoft). Features, integrations, deployment and the company behind each one, side by side. ## Our take What our shortlists say about each one. ### [Cisco Secure Email Threat Defense](https://cybersectools.com/tools/cisco-secure-email-threat-defense) Best for: Cisco shops wanting Talos-backed filtering It is on the list as a Microsoft 365 product that can grow with you: you start in API mode and add the inline gateway later, from the same console. That suits a team that already runs Cisco security. Check fit first if you run Google Workspace or your own mail servers, because the product is built for Microsoft 365. From [Best Email Security Solutions for Business](https://cybersectools.com/shortlists/best-email-security-platforms), Fall 2026. ### [Microsoft Defender for Office 365](https://cybersectools.com/tools/microsoft-defender-for-office-365) Best for: Teams running Microsoft 365 It is on the list because it is built into Microsoft 365, and many companies already own it through their license, so the buying question is often settled before you start. That makes it the natural first layer if you run Microsoft 365. Decide whether it covers your risk alone or needs a second product beside it, since it is built to work with other email security products. From [Best Email Security Solutions for Business](https://cybersectools.com/shortlists/best-email-security-platforms), Fall 2026. Reviewed by [Nika (Nikoloz) Kokhreidze](https://cybersectools.com/about). Need the answer fast? [Best Email Security Solutions for Business](https://cybersectools.com/shortlists/best-email-security-platforms) picks Proofpoint Core Email Protection, Microsoft Defender for Office 365, Mimecast Advanced Email Security and 4 more. ## Side-by-side comparison | | Cisco Secure Email Threat Defense | Microsoft Defender for Office 365 | |---|---|---| | Pricing model | Commercial | Commercial | | Category | Email Security Platforms | Email Security Platforms | | Verified | No | No | | Deployment type | Cloud | Cloud | | Company size fit | SMB, Mid-Market, Enterprise | SMB, Mid-Market, Enterprise | | Company | Cisco | Microsoft | | Headquarters | – | – | ### Use cases and capabilities | | Cisco Secure Email Threat Defense | Microsoft Defender for Office 365 | |---|---|---| | Microsoft 365 | Yes | Yes | | Threat Analysis | Yes | – | ### Core features **Cisco Secure Email Threat Defense** 9 features listed. Sign in on the page to see them. **Microsoft Defender for Office 365** 10 features listed. Sign in on the page to see them. ### Integrations **Cisco Secure Email Threat Defense** 3 integrations listed. Sign in on the page to see them. **Microsoft Defender for Office 365** 4 integrations listed. Sign in on the page to see them. ## Cisco Secure Email Threat Defense vs Microsoft Defender for Office 365 FAQ Common questions when comparing Cisco Secure Email Threat Defense vs Microsoft Defender for Office 365 for email security platforms. ### What is the difference between Cisco Secure Email Threat Defense and Microsoft Defender for Office 365? **Cisco Secure Email Threat Defense**: Email threat protection for Microsoft 365 with advanced detection capabilities. Built by Cisco. **Microsoft Defender for Office 365**: Email and collaboration security for Microsoft 365 environments. Built by Microsoft. The table above shows where their features, integrations, deployment and company size fit differ. ### Who makes Cisco Secure Email Threat Defense and Microsoft Defender for Office 365? **Cisco Secure Email Threat Defense** is made by Cisco. **Microsoft Defender for Office 365** is made by Microsoft. The vendor behind a product decides its roadmap, support, and longevity, so check each company's profile before you commit. ### Is Cisco Secure Email Threat Defense a good alternative to Microsoft Defender for Office 365? Often, yes. Cisco Secure Email Threat Defense and Microsoft Defender for Office 365 are both Email Security Platforms products, and both cover Microsoft 365. Use the table above to see where features, deployment and company size fit differ. ## Related comparisons - [Cisco Secure Email Threat Defense vs Ocean Agentic Email Security Platform](https://cybersectools.com/compare/cisco-secure-email-threat-defense-vs-ocean-agentic-email-security-platform) - [Cisco Secure Email Threat Defense vs KnowBe4 Cloud Email Security](https://cybersectools.com/compare/cisco-secure-email-threat-defense-vs-knowbe4-cloud-email-security) - [Cisco Secure Email Threat Defense vs ConnectWise Email Security](https://cybersectools.com/compare/cisco-secure-email-threat-defense-vs-connectwise-email-security) - [Microsoft Defender for Office 365 vs Ocean Agentic Email Security Platform](https://cybersectools.com/compare/microsoft-defender-for-office-365-vs-ocean-agentic-email-security-platform) - [Microsoft Defender for Office 365 vs KnowBe4 Cloud Email Security](https://cybersectools.com/compare/knowbe4-cloud-email-security-vs-microsoft-defender-for-office-365) - [Microsoft Defender for Office 365 vs ConnectWise Email Security](https://cybersectools.com/compare/connectwise-email-security-vs-microsoft-defender-for-office-365) ## Alternatives to each - [See all Cisco Secure Email Threat Defense alternatives](https://cybersectools.com/alternatives/cisco-secure-email-threat-defense) - [See all Microsoft Defender for Office 365 alternatives](https://cybersectools.com/alternatives/microsoft-defender-for-office-365) --- Source: https://cybersectools.com/compare/cisco-secure-email-threat-defense-vs-microsoft-defender-for-office-365 For AI agents: each product above has its own Markdown page (add .md to its URL, for example https://cybersectools.com/tools/cisco-secure-email-threat-defense.md). Every CybersecTools shortlist is listed at https://cybersectools.com/shortlists.md. More on Cisco Secure Email Threat Defense and Microsoft Defender for Office 365: funding, momentum, hiring and news, plus the full product and company record, are available through the Mandos MCP Server (paid plans), which connects to AI assistants: https://mandos.io/mcp?utm_source=cybersectools.com&utm_medium=compare-md