Challenging timetables, extreme requirements and increasing needs and expectations of stakeholders requires a new approach to project management and system engineering. Lean project development (i.e. Agile) is an emerging, promising methodology adapted by leading project management and systems engineering communities. The tools and techniques that can support this new methodology are being developed and tested by universities and industry.This article focuses on the use of Simulation Based Training (SBT) as a tool for training Systems Engineers and Project Managers in a Lean project environment.The Simulation Based Training (SBT) performed in this study is based on the Project Team Builder (PTB) simulator, which is an innovative project management and system engineering simulator designed as both a training/teaching tool and a decision support system for project teams.