Password sharing (or "account sharing") occurs when a user gives their login credentials to someone else for the purposes of shared access under one account. Password sharing has several ramifications for different parties. The largest risk involved in sharing passwords is the obvious security risk of trusting the other person that now has access.

For example, if a user shares their computer password with a colleague for whatever reason (usually convenience), that colleague now has access to much more than they should (breaking the concept of least privilege). Sharing passwords is not recommended in any situation, but if someone does have access to a user's account, it is highly recommended that the users change their password immediately.

Another reason for many people sharing passwords is to share the benefits of the account such as a streaming service (Netflix, Hulu, Amazon Prime, CBS, etc.). Account sharing has resulted in significant lost revenue for streaming services.