KeePass Password Safe is a free and open-source password manager primarily for Windows. It officially supports macOS and Linux operating systems through the use of Mono. Additionally, there are several unofficial ports for Windows Phone, Android, iOS, and BlackBerry devices, which normally work with the same copied or shared (remote) password database. KeePass stores usernames, passwords, and other fields, including free-form notes and file attachments, in an encrypted file. This file can be protected by any combination of a master password, a key file, and the current Windows account details. By default, the KeePass database is stored on a local file system (as opposed to cloud storage).

KeePass comes in two different variants: KeePass 1.x and KeePass 2.x. Although the 1.x variant is the former variant it is supported indefinitely: Dominik Reichl: "2.x isn't the successor of 1.x, and 1.x isn't dead". KeePass 2.x has a different software basis in C# instead of the former C++. Mainly communication features are extended in KeePass 2.x: authentication with the Windows user account, remote and shared database editing as well as many plugins allowing communication and authentication with different web browsers, databases and more.

KeePass 1.x and 2.x support a number of plugins, although 2.x allows more plugins. It has a password generator and synchronization function, supports two-factor authentication, and has a Secure Desktop mode. It can use a two-channel auto-type obfuscation feature to offer additional protection against keyloggers. KeePass can import from over 30 other most commonly used password managers.

A 2017 Consumer Reports article described KeePass as one of the four most widely used password managers (alongside 1Password, Dashlane and LastPass), being "popular among tech enthusiasts" and offering the same level of security as non-free competitors.

A 2019 Independent Security Evaluators study described KeePass as well as other widely used password managers as being unable to control Windows 10's tendency to leave passwords in cleartext in RAM after they are displayed using Windows controlled GUI. In addition, several GitHub projects (KeeFarce, KeeThief, Lazanga) specifically attack a running KeePass to steal all data when the host is compromised. KeePass cannot prevent password theft and, as Dominik Reichl, the administrator of KeePass, states, "neither KeePass nor any other password manager can magically run securely in a spyware-infected, insecure environment."

The password list is saved by default as a .kdbx file, but it can be exported to .txt, HTML, XML and CSV. The XML output can be used in other applications and re-imported into KeePass using a plugin. The CSV output is compatible with many other password safes like the commercial closed-source Password Keeper and the closed-source Password Agent. Also, the CSVs can be imported by spreadsheet applications like Microsoft Excel or OpenOffice/LibreOffice Calc.

File format support can be expanded through the use of KeePass plugins.

KeePass supports simultaneous access and simultaneous changes to a shared password file by multiple computers (often by using a shared network drive), however there is no provisioning of access per-group or per-entry. As of May 2014, there are no plugins available to add provisioned multi-user support, but there exists a proprietary password server (now titled Keepass Hub, formerly known as Pleasant Password Server) that is compatible with the KeePass client and includes provisioning.