Project management software is a term covering many types of software, resource allocation, collaboration software, communication or administration systems, which are used to deal with the complexity of large projects.

The following may apply in general, or to specific products, or to some specific functions within products.
May not be derived from a sound project management method. For example, displaying the Gantt chart view by default encourages users to focus on timed task scheduling too early, rather than identifying objectives, deliverables and the imposed logical progress of events (dig the trench first to put in the drain pipe).
Similar to PowerPoint, project management software might shield the manager from important interpersonal contact.
New types of software are challenging the traditional definition of Project Management. Frequently, users of project management software are not actually managing a discrete project. For instance, managing the ongoing marketing for an already-released product is not a "project" in the traditional sense of the term; it does not involve management of discrete resources working on something with a discrete beginning/end. Groupware applications now add "project management" features that directly support this type of workflow-oriented project management. Classically-trained Project Managers may argue whether this is "sound project management." However, the end-users of such tools will refer to it as such, and the de-facto definition of the term Project Management may change.

An integrated system combines project management or project planning, with many other aspects of company life. For example, projects can have bug tracking issues assigned to each project, the list of project customers becomes a customer relationship management module, and each person on the project plan has their own task lists, calendars, and messaging functionality associated with their projects.

Similarly, specialised tools like SourceForge integrate project management software with source control (CVS) software and bug-tracking software, so that each piece of information can be integrated into the same system.

Project management software can be implemented as a program that runs on the desktop of each user. This typically gives the most responsive and graphically-intense style of interface.

Desktop applications typically store their data in a file, although some have the ability to collaborate with other users (see below), or to store their data in a central database. Even a file-based project plan can be shared between users if it's on a networked drive and only one user accesses it at a time.

Desktop applications can be written to run in a heterogeneous environment of multiple operating systems, although it's unusual.

A collaborative system is designed to support multiple users modifying different sections of the plan at once; for example, updating the areas they personally are responsible for such that those estimates get integrated into the overall plan. Web-based tools, including extranets, generally fall into this category, but have the limitation that they can only be used when the user has live Internet access. To address this limitation, client-server-based software tools exist that provide a Rich Client that runs on users' desktop computer and replicate project and task information to other project team members through a central server when users connect periodically to the network. Some tools allow team members to check out their schedules (and others' as read only) to work on them while not on the network. When reconnecting to the database, all changes are synchronized with the other schedules.