This volume of Advances in Intelligent Systems and Computing highlights papers presented at the 12th International Conference on Genetic and Evolutionary Computing (ICGEC 2018). Held from 14 to 17 December 2018 in Changzhou, Jiangsu, China, the conference was co-sponsored by Springer, Changzhou College of Information Technology, Fujian Provincial Key Lab of Big Data Mining and Applications, Fujian University of Technology, National Demonstration Center for Experimental Electronic Information and Electrical Technology Education, Fujian University of Technology, Tajen University, National University of Kaohsiung, and Shandong University of Science and Technology, China. The conference is intended as an international forum for the researchers and professionals in all areas of genetic and evolutionary computing.