The complexity of a vehicle and also of its subsystems such as powertrain, electrics/electronics (E/E), thermal management system, chassis, body, or driving assistance is increasing due to the growing number of interacting functions and (mechatronic) systems. This results in the need to continuously coordinate, monitor, adjust, and optimize development tasks across departments and company boundaries and even globally. Managing this organizational and technological complexity for powertrain development and its interfaces upwards to vehicle development and downwards to the powertrain’s elements and their production requires a structured powertrain development process that must be followed accordingly. Merely focusing on individual elements or even subsystems without considering process and technical interfaces between them is insufficient. The integration of the powertrain elements in the powertrain and further into the vehicle and other vehicle systems is an essential target of the development process. This chapter provides insights into a powertrain development process for passenger cars.