OU or Ou or ou may stand for:
Outlook.com is a web-based suite of webmail, contacts, tasks, and calendaring services from Microsoft.
Outsourcing is "an agreement in which one company hires another company to be responsible for an existing internal activity." It often involves the contracting of a business process (e.g., payroll processing, claims processing), operational, and/or non-core functions, such as manufacturing, facility management, call center support).
Outlander is a drama television series based upon author Diana Gabaldon's historical time travel book series of the same name.
An outlaw motorcycle club is a motorcycle subculture that has its roots in the immediate post-World War II era of North American society.
The Outer Hebrides (), also known as the Western Isles (Scottish Gaelic: Na h-Eileanan Siar [nə ˈhelanən ˈʃiəɾ] or Na h-Eileanan an Iar [nəˈhelanən əˈɲiəɾ]), Innse Gall ("islands of the strangers") or the Long Isle or the Long Island (Scottish Gaelic: An t-Eilean Fada), is an island chain off the west coast of mainland Scotland.
The following outline is provided as an overview of and topical guide to geography: