Lean Manufacturing has been for years a successful paradigm that leads companies to operational excellence. However, changes in the market that require cheap mass customization seem beyond the scope of lean manufacturing, which relies on more stable schedules. Meanwhile, Industry 4.0 appears as one of the most promising approaches for dealing with future challenges in manufacturing environments through automation and data exchange thanks to cyber-physical systems and the Internet of Things. The relationship between lean manufacturing and Industry 4.0 attracts management scholars and the number of contributions that can be found in the literature is increasing quickly. However, the lack of real implementations leads to conceptual papers based on hypothetical outcomes on a number of aspects. The aim of this research paper is to explore and evaluate, through a systematic review of the literature up to September 2019, previous work focusing on the relationship and links between lean manufacturing and Industry 4.0, in order to understand whether lean manufacturing and Industry 4.0 can be integrated to achieve synergies between the two approaches. Besides, a bibliometric study is performed. Although different scenarios are considered possible, most relate to lean tools being enhanced by real-time information. The majority present an evolution, not a revolution. Lean manufacturing offers stable processes where automatization and digitalization can be successfully implemented. Otherwise, new technologies will fail to make the most of poorly managed processes. The role of employees has not been addressed in the reviewed literature.