What are the five process groups in project management?

The five process groups defined in the PMBOK Guide are initiating, planning, executing, monitoring and controlling, and closing. Initiating defines and authorizes the project through the project charter. Planning establishes scope, schedule, cost, and other baselines. Executing carries out the project management plan by coordinating people and resources. Monitoring and controlling tracks progress, compares actual performance against the plan, and manages changes. Closing formally completes the project and captures lessons learned.