To connect Slack to Outlook Calendar, add the official Outlook Calendar app to Slack, open its Home tab, and select Connect an account to sign in with your eligible Microsoft 365 account. After connecting, you can choose calendars, adjust reminders, and turn on automatic Slack status updates.
The integration works with eligible Office 365 or Microsoft 365 cloud calendars. Slack excludes on-premises Exchange and Microsoft national-cloud deployments, so check your account’s eligibility before starting.
The short version
- Install the app: Add the official Outlook Calendar app from Slack Marketplace or Slack’s desktop app browser.
- Connect your account: Open the app’s Home tab and select Connect an account.
- Choose calendars: Select calendars belonging to your connected account under Accounts.
- Customize delivery: Adjust calendar notifications and enable Status Sync for your primary calendar.
| Task | Where to start | Purpose or requirement |
|---|---|---|
| Install from Marketplace | Add to Slack | Add the official integration |
| Install inside Slack | Agents & tools > Apps | Find Outlook Calendar on desktop |
| Connect your account | Home > Connect an account | Authenticate your eligible Microsoft account |
| Select calendars | Settings > Accounts | Choose calendars belonging to your account |
| Sync your status | Settings > Status Sync | Use your primary calendar |
| Configure notifications | Settings > Notification Preferences | Adjust calendar notifications and desktop delivery |
| Disconnect or reconnect | App Settings or Marketplace Configuration | Disconnect a calendar or repair authorization |
| Schedule a meeting | Outlook Calendar’s Home tab | Create an event using your connection |
| Request installation approval | Apps > Add > Add to Slack | Submit a request when approval is required |
| Preapprove the app | Admin > Apps and workflows | Workspace owner approval |
| Connect a domain | Settings > Domain-wide Authentication | Administrator setup and domain verification |
| Build a Slack workflow | Agents & tools > Workflows | Calendar automation on paid Slack plans |
| Remove the workspace integration | Tools & settings > Manage apps | Removal can affect other members |
| Connect Outlook to Zapier | Apps > + Add connection | Eligible business account with Exchange Online |
| Build a Zapier automation | Microsoft Outlook and Slack | Reminders, custom statuses, or event creation |
| Create a Power Automate flow | Open My flows | Connect an Outlook trigger to Slack |
| Choose an Outlook trigger | Office 365 Outlook connector | New events, reminders, or calendar changes |
| Post calendar information to Slack | Post message (V2) | Configure the destination and message |
| Create a flow with Copilot | Power Automate’s Copilot field | Generate and review a flow where Copilot is available |
Add the Outlook Calendar app to Slack
Open the official Outlook Calendar app page and select Add to Slack. Select Allow, then select Open Slack to return to Slack.
You can also install the integration from Slack on desktop. Open Agents & tools > Apps, search for Outlook Calendar, and select Add > Add to Slack. Complete authorization to finish adding it; depending on your sidebar layout, look under Tools or More to find the app browser.
If Slack asks you to request approval, enter the requested explanation and select Submit. Wait for Slack’s approval notification before completing installation. Apps marked as restricted cannot be requested through this route.
Connect your account and choose calendars
On desktop, open Agents & tools > Apps, select Outlook Calendar, and open Home. Select Connect an account. Sign in only through Microsoft’s own app or website, and never share a code, password, or remote access with someone who contacts you. Complete authentication, then select Open Slack.
On mobile, open Slack’s Home tab and tap Jump to. Find and open Outlook Calendar, open its Home tab, and select Connect an account. Complete authentication, then tap Done.
To choose calendars on desktop, open Outlook Calendar’s Home tab and select Connect Calendar, or open Settings for an existing connection. Under Accounts, select the calendars you want to connect, then select Done. These choices are calendars belonging to the connected account.
For calendar selection on mobile, open the app’s Settings. Select your calendars under Accounts, then tap Done.
Set notifications and automatic status updates
Open Outlook Calendar > Home > Settings > Notification Preferences. Adjust the preferences for your connected calendars, then select Update.
On desktop, select your profile picture and open Preferences > Notifications, then find Calendar notifications and open How to notify you. Check In the sidebar for sidebar delivery, and check As system notifications for system notifications.
To enable automatic status updates, open Outlook Calendar > Home > Settings. Select Status Sync and switch it on. Status syncing uses your primary calendar only, even when you connect additional calendars for notifications.
Schedule a meeting from Slack
On desktop, open Agents & tools > Apps > Outlook Calendar > Home. If your account still needs connecting, select Connect an account and complete authentication first. Select Create event to schedule a meeting. Scheduling through the app uses the Outlook connection you already established.
Repair or disconnect an existing connection
If an existing connection fails, you can revoke its authorization and reconnect. Revoking authorization removes the existing authorization for the app. On the Outlook Calendar Marketplace page, open Configuration, find Your Authorization, and select Revoke. Reload the page, then select Add to Slack and complete authorization.
Disconnecting a calendar removes its connection to Slack. To disconnect it, open Outlook Calendar’s Home > Settings and select Disconnect Calendar. Select Yes to confirm.
Removing the workspace integration removes the app and can affect other workspace members. If you have permission to remove apps, select your workspace name, then open Tools & settings > Manage apps > Installed Apps > Outlook Calendar > App Details > Configuration. Select the pencil icon, then select Remove; with one configuration, select Remove at the top instead. When app approval is enabled, only workspace owners and app managers can remove apps.
Approve the app or connect a domain
If you are a workspace owner, open Admin > Apps and workflows > Browse. Search for Outlook Calendar, select it, then select Approve. Workspace owners control approval policy through App management settings, and Enterprise organization policies can also govern availability.
Domain-wide authentication is available to workspace owners and admins on Free, Pro, and Business+, and organization owners and admins on Enterprise. You also need an Office 365 administrator, and Slack email addresses must match Microsoft Azure UPNs.
Install Outlook Calendar, then open Agents & tools > Apps > Outlook Calendar > Home > Settings > Domain-wide Authentication. Select Add domain, enter the domain, and select Add. Open the domain’s authorization URL and sign in as the Office 365 administrator. Select Accept, then select Open Slack.
Open the domain-ownership verification URL in Settings. Check the consent checkbox, select Accept, then select Open Slack. In Settings, select Verify beside the domain, enter a domain email address, and select Verify again. On Enterprise, use Choose to select participating workspaces.
Create calendar automations with Workflow Builder
Slack Workflow Builder supports Outlook Calendar connector steps on paid plans for eligible full members with Workflow Builder access. Connector approval may be required. These workflows create calendar automations rather than enabling the personal status-sync feature.
Open Agents & tools > Workflows > New > Build Workflow. Under Start the workflow, select Choose an event, configure the trigger, and select Continue. Find a Microsoft Outlook Calendar connector step, authenticate your Microsoft account, configure the step, and select Save. Select Finish Up, review permissions, then select Publish.
Build an Outlook and Slack automation in Zapier
Zapier’s Microsoft Outlook connection requires Microsoft 365 Business or Enterprise with an Exchange Online mailbox. Organization consent restrictions may require administrator approval. These automations can send reminders, change a Slack status, or create calendar events, but they are not automatic full two-way calendar synchronization.
In Zapier, open Apps > + Add connection. Search for Microsoft Outlook and select Add connection. Authenticate in the Microsoft window and complete the permissions prompt.
For calendar reminders, build an automation pairing Microsoft Outlook’s Calendar Event Start with Slack’s Send Channel Message. Configure Channel and Message Text for the notification.
For custom status changes, use Slack’s Set Status action. Configure Status Text, Status Emoji, and Expiration Time.
For Slack-to-Outlook event creation, use a supported Slack trigger with Outlook’s Create Event action. Supply Calendar, Subject, Start Date & Time, and End Date & Time. Whichever automation you choose, authenticate both services and test it before enabling it.
Send calendar updates through Power Automate
Power Automate can connect an Office 365 Outlook calendar trigger to a Slack posting action. You need an eligible Office 365 Outlook account and a permitted Slack connection; tenant policies and connector availability apply.
Sign in to Power Automate, open My flows, then select Create from blank > Add a trigger. Choose an Office 365 Outlook calendar trigger and authenticate your account.
For newly created appointments, select When a new event is created (V3). For reminders, select When an upcoming event is starting soon (V3), then configure Calendar Id and Look-Ahead Time. For changes and cancellations, select When an event is added, updated or deleted (V3).
In the new designer, select the plus sign after the trigger and add Slack’s Post message (V2). Authenticate Slack, then set Channel Name and Message Text, inserting calendar information from the Outlook trigger. Select Save and test the flow.
If an existing flow uses Post message [DEPRECATED], replace it with Post message (V2), review field mappings, and test. Replace When an upcoming event is starting soon (V2) or When an event is added, updated or deleted (V2) with its V3 equivalent. Recheck the calendar selection and downstream mappings after replacing a trigger.
If your Power Automate environment has Copilot access, enter a description of the desired calendar-to-Slack automation in the Copilot field and select Submit. Review the generated operations, then select Keep it and continue. Review connections, select Create flow, then configure and save the flow. Generated flows still require supported connectors and authentication.
Frequently Asked Questions
Is having Outlook installed on my computer enough?
No, a locally installed Outlook application alone does not establish eligibility for Slack’s Outlook Calendar integration. Your account must have an eligible Office 365 or Microsoft 365 cloud calendar.
Does everyone need to install the Outlook Calendar app separately?
The app is installed once per Slack workspace. Each member then connects their account individually.
Can I use a personal Outlook.com account with Zapier for this?
No, Zapier excludes personal Outlook.com, Office Home, and Live.com accounts from its Microsoft Outlook connection. It requires Microsoft 365 Business or Enterprise with an Exchange Online mailbox.
Can Power Automate send calendar messages to a private Slack destination?
Yes, Microsoft’s Slack connector supports destinations that can include private groups and direct-message channels. Supported channels are also available as destinations.
Is there a Slack workflow template for Outlook Calendar?
Yes, Slack Marketplace offers the New Microsoft Outlook calendar event template. You need an eligible paid-plan account with Workflow Builder access, and connector approval may be required.