The fourth industrial revolution, also known as Industry 4.0, implies significant new technological opportunities for today’s manufacturing industry. However, manufacturing companies still lack knowledge and skills on how to fully utilize these innovative technologies. This is in particular the case as regards development of process innovation. In order to advance this knowledge, the concept of learning factories is useful to support the manufacturer’s learning and movement towards innovation. In short, a learning factory, that supports process innovation, can be described as a learning process for industry participants, which utilizes a learning factory to create rapid and innovative process solutions in industry based on the paradigm of Industry 4.0. Research on this topic is however still relatively scarce and scattered, meaning that no common conceptual frame of reference exists to support the research field of process innovation. Consequently, the theory building on innovation in the context of i4.0 is still fragmented and in its infancy, in spite of the rapidly increasing interest in this empirical phenomenon. To advance this domain of research, the current study unites and synthesizes existing research on process innovation in learning factories. Based on the findings of the literature review, the initial work of a reference model for process innovation in learning factories is presented.