Office 365 is the brand name that Microsoft uses for a group of software and services subscriptions, which together provide productivity software and related services to their subscribers.

For business users, Office 365 offers service plans providing e-mail and social networking services through hosted versions of Exchange Server, Skype for Business Server, SharePoint and Office Online, and integration with Yammer, as well as access to the Microsoft Office software.

On April 21, 2020, the consumer and small business plans of Office 365 were renamed Microsoft 365 to emphasize their current inclusion of products and services beyond the core Microsoft Office software family (including cloud-based productivity tools and artificial intelligence features). Most products that were called Office 365 were renamed as Microsoft 365 on the same day.

Microsoft 365 encompasses subscription plans that allow use of the Microsoft Office software suite over the life of the subscription, as well as cloud-based software-as-a-service products for business environments, such as hosted Exchange Server, Skype for Business Server, and SharePoint, among others.

The Office 365 branding remains in use for subscription plans targeting some enterprise markets.