How to Set Up a Shared Address Book in Microsoft Teams

The fastest way to set up a shared address book in Microsoft Teams is with an app built for the job: install the app from the Teams store, pin it as a tab in a team, import your existing contacts from Outlook or via CSV and define permissions - and your whole team has a central address book, usually in under an hour. Microsoft 365's built-in options like the Global Address List cover parts of the job but quickly hit their limits in daily work: external contacts can hardly be maintained together, changes stay stuck in individual mailboxes, and nobody knows which version is current. This guide covers both routes - including a step-by-step walkthrough your team can follow right away.

Why a shared address book in Microsoft Teams?

In most companies, customer contacts are scattered across personal Outlook mailboxes. Every team knows the consequences: a colleague is on holiday and nobody can find the direct line of the key account contact. Someone leaves the company - and their contacts leave with them. Two people maintain the same contact twice, each with a different version.

A shared address book solves exactly these problems: everyone works with the same, always up-to-date data. And when that address book lives directly in Microsoft Teams, there is no switching to a separate tool - contact management happens where the team already works.

What does Microsoft 365 offer out of the box - and where are the limits?

Microsoft 365 ships with several building blocks that look like a shared address book at first glance:

• Global Address List (GAL): shows all internal mailboxes and IT-managed contacts. It is not designed for external customer and supplier contacts that the team should maintain itself.
• Shared mailboxes: allow a shared contacts folder, but offer no fields for company, industry or team-level notes - and no editing history.
• Microsoft 365 groups: great for collaborating on files and mail, but without structured contact management.

For small teams with a few dozen contacts, these built-in tools can be enough. But as soon as several people actively maintain external contacts, discuss topics per contact or need differentiated permissions, a dedicated solution is required - either a full CRM or a lightweight contact management tool like Company Contacts von timeghost, which integrates directly into Teams as an app.

Step by step: setting up a shared address book with a Teams app

Here is how to set up a shared address book, using Company Contacts as the example:

1. Install the app: Open the Apps section in Microsoft Teams, search for the contact management app and add it. Sign-in works via single sign-on with your Microsoft account - no separate login needed.
2. Pin it as a tab: Add the app as a tab in the team or channel where your team works. That makes the address book one click away for everyone.
3. Import existing contacts: Bring in contacts from Outlook and Active Directory via sync, or import existing lists as a CSV file.
4. Create companies: Group contacts by company, including industry, address and website. This makes searching easier later and creates a clear overview.
5. Define permissions: Decide who can see and edit which contacts - for example separated by sales, service and management.
6. Brief your team: Show your colleagues briefly where the address book lives and how new contacts are created. Fifteen minutes is usually enough.

You can find an overview of all Company Contacts features on our website.

How do existing contacts get into the shared address book?

In practice, the import is the biggest hurdle - and at the same time the most important step, because nobody uses an empty address book. Three approaches have proven themselves:

• Outlook and Active Directory sync: Existing contacts are taken over automatically and kept up to date. This is the fastest way to build the base.
• CSV import: Excel lists, trade fair contacts or exports from legacy systems can be imported as CSV files. Pay attention to clean column mapping to avoid duplicates.
• Email signature scanning: Company Contacts automatically detects contact details from the signatures of incoming and outgoing emails, suggests new contacts and updates existing ones - every suggestion is confirmed before it is applied. This way, the address book practically fills and maintains itself in daily use.

Who is allowed to do what? Setting up permissions properly

A shared address book does not mean everyone has to see everything. A simple model works well: general company contacts are visible to everyone, sensitive contacts - such as applicants, management advisors or press lists - only to the relevant group. Define this structure before the big import, so you do not have to reorganise later. Also review permissions once or twice a year: teams change, and so do access needs. From a data protection perspective, a clean permission concept is mandatory anyway - the GDPR requires that personal data is only accessible to those who need it for their work.

Common mistakes during setup - and how to avoid them

• Importing everything at once: An unfiltered import of ten-year-old contact lists mostly creates data waste. Start with the active contacts of the last two to three years.
• No ownership: Without clear responsibility, every address book goes stale. Appoint one person per team who spot-checks data quality.
• Adding permissions later: Opening everything up first and restricting it later causes irritation. Concept first, then import.
• Treating the address book as a data graveyard: The value comes from the team actively working with it - for example tracking topics and tasks directly on the contact instead of losing them in email threads.

Conclusion: a central address book in one hour

Setting up a shared address book in Microsoft Teams is not a major IT project: install the app, bring in contacts via Outlook sync or CSV, define permissions - and your team works with a shared, current contact base from day one. Microsoft 365's built-in tools are rarely enough for this, while a full CRM is oversized for many teams. Company Contacts von timeghost closes exactly this gap: a central address book, Outlook sync, signature detection and a topic board directly in Microsoft Teams, GDPR compliant and made in Germany. You can find the package details on the pricing page - or get started right away and try Company Contacts for free in your Microsoft Teams.

Sources and further reading

• Microsoft Learn: Microsoft Teams documentation
• Microsoft Learn: Outlook contacts in Microsoft Graph (overview)
• Microsoft Learn: Microsoft 365 admin documentation
• EUR-Lex: Regulation (EU) 2016/679 (GDPR)

This article is for general information purposes. The content was created with the support of AI and reviewed editorially. Last updated: 2026-08-08.

Frequently asked questions

Can I sync Outlook contacts into a shared address book automatically?

Yes. Contact management apps like Company Contacts von timeghost automatically sync existing contacts from Outlook and Active Directory into the shared address book. New or changed contact details can also be detected from email signatures and added after your confirmation, so there is no duplicate maintenance.

Isn't the Global Address List (GAL) enough as a shared address book?

The Global Address List mainly shows internal people and is maintained centrally by IT. External contacts such as customers, suppliers or partners cannot be managed collaboratively there, commented on or linked to tasks. For jointly maintained company contacts you need a dedicated solution.

Who can see and edit the contacts in a shared address book?

You control this through permissions. In Company Contacts, permission groups define exactly which team members can see and edit which contacts. Confidential management contacts stay protected, while the sales team keeps full access to its customer contacts.

Is a shared address book in Microsoft Teams GDPR compliant?

That depends on the solution you use. Look for data processing in the EU, a clear permission concept and a data processing agreement. Company Contacts is GDPR compliant and ISO 27001 compliant and is developed in Germany. The legal assessment for your specific case should always involve your data protection officer.