This study presents a systematic literature review of the recent scholarly literature on product complexity (number, diversity, and interrelatedness of product variants and components) and operational performance (measured in terms of cost, time quality, and delivery reliability) in manufacturing and supply chain firms, considering the manufacturing context as well as the mechanisms behind the relationships. The results show that product complexity has a consistently negative relationship with cost, time, quality, and delivery performance measures, though the relationships with quality and delivery performance are less clear. (C) 2019 CIRP.