This book includes extended and revised versions of selected papers from the 9th and 10th edition of the International Conference on Operations Research and Enterprise Systems (ICORES 2020 and ICORES 2021). ICORES 2020 was held in Valletta, Malta from 22 – 24 of February 2020, and ICORES 2021 was held as an online event due to the Covid-19 pandemic, from 4 – 6 of February 2021.

The 11 full papers included in this book were carefully reviewed and selected from 132 submissions. The ICORES 2020 and 2021 book contains extended and revised version of proceedings papers dealing with operations research and enterprise systems.