Microsoft Teams vs Slack

Microsoft Teams vs Slack is a comparison between a suite component and a specialist. Teams is chat, meetings, telephony, files, and an app platform inside Microsoft 365, included in the licence most organisations already have, and governed by the same identity, compliance, and security tools as email and SharePoint. Slack is the better pure chat product — cleaner, faster, with a deeper developer-tool ecosystem and a culture it created — and is now owned by Salesforce, which shapes its roadmap toward CRM and AI agents. For a Microsoft 365 organisation, Slack is a deliberate extra cost that has to be justified by the chat experience; for a Google Workspace or developer-led organisation, Slack is often the default and Teams the outsider.

What Teams is and how it fits — the group-backed architecture, channels, meeting policies, Teams Phone — is in What is Microsoft Teams. The meetings-focused sibling comparison is Teams vs Zoom.

Where each one comes from

Slack (2013) defined modern workplace chat: channels, threads, emoji reactions, search that works, and an integration model that made it the notification hub for engineering and product teams. Huddles added lightweight audio/video; Canvas added documents; Workflow Builder added no-code automation. Salesforce bought it in 2021 and has since pushed Slack AI, Agentforce integration, and Salesforce data in Slack. Enterprise Grid supports very large multi-workspace organisations.

Microsoft Teams (2017) is the collaboration hub of Microsoft 365: persistent chat and channels backed by Microsoft 365 groups and SharePoint, meetings with recording, transcription, and Copilot, a full phone system, Teams Rooms hardware, and an app platform (tabs, bots, message extensions) with Power Platform integration. It is governed by Entra ID, Purview (retention, DLP, eDiscovery, labels), and Defender — the same controls as the rest of the suite. Since 2023 Microsoft has rebuilt the client for performance and, under regulatory pressure, unbundled Teams from enterprise suites in some markets.

Decision criteria

| Criterion | Microsoft Teams | Slack | | --- | --- | --- | | Chat experience | Improved with the new client; still heavier | Best in class; fast, clean, threads work | | Meetings | Full featured; webinars, town halls, Rooms, Premium | Huddles for quick calls; Zoom/Teams for real meetings | | Telephony | Teams Phone, a real PBX replacement | None (integrations) | | Files | SharePoint/OneDrive native, co-authoring | Attachments; integrations to Drive/OneDrive/Box | | Integrations | Large; strongest for Microsoft and enterprise apps; Power Automate | Largest catalogue; strongest for developer tools; Workflow Builder | | External collaboration | Guests, external access (federation), shared channels via B2B direct connect | Slack Connect (shared channels across orgs) — smoother | | Governance & compliance | Purview retention, DLP, eDiscovery, labels, information barriers | Enterprise Grid: retention, DLP via partners, eDiscovery export; less integrated | | Identity & security | Entra native; Conditional Access; Defender | SAML SSO, SCIM; security via partners | | AI | Copilot in Teams (add-on), intelligent recap (Premium) | Slack AI (add-on), Agentforce | | Price | Included in most M365 plans (see FAQ) | Separate per-user subscription (Pro/Business+/Enterprise Grid) |

Cost model

Teams is included in Microsoft 365 Business Basic/Standard/Premium and, outside the "no Teams" enterprise SKUs, in E3/E5 and F-plans; where unbundled, Teams Enterprise is approximately 5.25 USD per user per month (as of 2026-09; check Microsoft). Teams Premium (approximately 10 USD) and Copilot (approximately 30 USD) are add-ons. Teams Phone and calling plans are extra.

Slack is per active user per month with Pro, Business+, and Enterprise Grid tiers, annual billing cheaper; Slack AI is an add-on. For an organisation on Microsoft 365, running Slack is typically the cost of a second collaboration platform per user on top of a licence that already includes one — plus the governance work of applying retention and eDiscovery to a second system. Run the numbers in the licensing calculator for the Microsoft side.

Choose Teams if

• The organisation runs on Microsoft 365 and the goal is one governed platform for chat, meetings, files, and phone.
• Compliance matters: retention, DLP, eDiscovery, information barriers, and sensitivity labels are required on chat, not just email — see Teams chat retention.
• Meetings and telephony are core; Teams Rooms, webinars, and Teams Phone replace other products.
• Frontline workers need Shifts, Walkie Talkie, and cheap F-plan licences.

Choose Slack if

• Engineering and product culture is Slack-native and the developer-tool integrations are load-bearing.
• The organisation is on Google Workspace, or is multi-vendor by design and does not want collaboration tied to Microsoft.
• Slack Connect with customers and partners is a business practice, not an exception.
• The chat experience is a hiring and retention issue and leadership accepts the cost.

Run both if

You must — an acquisition, or an engineering org that will not move. Set a governance floor for Slack (SSO, SCIM, retention, DLP via a partner), decide where meetings happen, and set a date to converge. Two chat platforms is the most expensive collaboration configuration there is: every announcement posted twice, every incident channel duplicated. The after-acquisition guide covers the tenant side of that situation.

What people get wrong

Judging Teams on the 2020 client. Judging Slack on chat alone when the actual requirement includes meetings, phone, and compliance. Treating the "Teams is free" argument as decisive without costing the governance gap Slack leaves. And migrating Slack to Teams without redesigning channels — the Teams channels guide is the place to start, because Slack workspaces and Teams teams do not map one to one.