In recent decades, the diversification of automated learning applications has led to new requirements inherent in the availability of large-scale data. Given the new scientific and technological challenges that are encountered, mathematical optimization has been established as the right approach for many Machine Learning problems. The specific requirements of machine learning raise new challenges for optimization. In turn, optimization takes advantage of machine learning insofar as concepts, formalisms, approximations and algorithms are revisited. LOPAL’2020 will be a relevant opportunity for researchers, practitioners, and educators around the world to present and discuss the most recent innovations, trends, and concerns together with the theoretical and practical challenges encountered and their applications.